JP2007127787A - Method for manufacturing display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a display device efficiently with high precision. <P>SOLUTION: A plurality of liquid crystal display devices 1 are manufactured from a laminated substrate 30 by forming the laminated substrate 30, and performing processes to: form a plurality of liquid crystal layers by arranging them between a pair of substrate base materials 31, 32 constituting the laminated substrate 30 in a matrix; stick polarizing plates 23, 24 to the laminated substrate 30; partly remove the polarizing plates 23, 24 from surfaces of the laminated substrate 30; and segment the laminated substrate 30 at removal regions J1, J2 from which the polarizing plates 23, 24 have been removed, wherein speed of removing the polarizing plates 23, 24 is made higher than that of segmenting the substrate base materials 31, 32. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a display device such as a liquid crystal display device.

  The liquid crystal display device is suitably used as a display unit of mobile devices such as a mobile phone, a digital still camera, and a PDA (personal digital assistant). In recent years, since these mobile devices tend to be thin, liquid crystal display devices are required to be thinner.

  In general, a liquid crystal display device includes a pair of glass substrates disposed opposite to each other, and a liquid crystal layer sealed between the pair of glass substrates. A transparent electrode, an alignment film, and the like are formed on the inner surface of each glass substrate (that is, the surface on the liquid crystal layer side). On the other hand, an optical film such as a polarizing plate is provided on the outer surface of each glass substrate (that is, the surface opposite to the liquid crystal layer).

  On the other hand, many studies have been made to reduce the thickness of a liquid crystal display device by thinning a glass substrate. As a method of reducing the thickness of the glass substrate, for example, a method of mechanically polishing the glass substrate can be considered. However, with this mechanical polishing method, it is difficult to polish the surface of the glass substrate flat, and the liquid crystal display device cannot be manufactured efficiently. Therefore, the glass substrate is usually thinned by etching (see, for example, Patent Document 1). In Patent Document 1, each glass substrate is thinned by immersing the entire pair of glass substrates in an etching solution.

  However, when both surfaces of a pair of glass substrates are etched as in Patent Document 1, sufficient strength cannot be obtained when the thickness of one glass substrate is less than 0.5 mm, and the glass substrate is cracked. There is a problem that it becomes easy to do. Therefore, it is not practical to make the total thickness of the pair of glass substrates less than 1 mm by this method.

  On the other hand, by forming one glass substrate thinner than the other glass substrate, it is known to reduce the overall thickness while ensuring strength with a relatively thick glass substrate (for example, Patent Document 2). reference). In Patent Document 2, the thickness of the other glass substrate is reduced by immersing one glass substrate in an etching solution while being covered with a resist mask.

  By the way, in manufacturing a conventional liquid crystal display device (particularly a small liquid crystal display device applied to a mobile phone or the like), a large glass substrate (substrate base material) is divided into several hundred pieces. A liquid crystal panel is manufactured. In this case, as shown in FIG. 8, first, a pair of substrate base materials 101 are bonded together, and liquid crystal is injected and sealed. Thereafter, as shown by broken lines in FIG. 8, the pair of substrate base materials 101 are divided to manufacture a plurality of panels 103. Subsequently, an optical film 104 such as a polarizing plate is attached to each panel 103.

However, it takes a lot of work to individually attach the optical film 104 to each of the plurality of panels 103 in this way. Therefore, it is known to divide a pair of substrate base materials after attaching a large optical film (see, for example, Patent Document 3). In this case, as shown in FIG. 9, a large optical film 104 is bonded in advance to a pair of substrate base materials 101 bonded together. Thereafter, the optical film 104 is partially removed from the pair of substrate base materials 101 in a band shape. Subsequently, the substrate base material 101 is divided along the strip-shaped removal region from which the optical film 104 has been removed, and a plurality of panels 105 are manufactured. As a result, the divided optical film 104 is attached to each panel 105. By doing in this way, it becomes possible to reduce a man-hour significantly.
Japanese Patent Laid-Open No. 4-116619 JP-A-5-249422 JP 2004-4636 A

  However, as a result of extensive research conducted by the present inventors, depending on the dividing speed, cracks occur in the substrate base material, making it difficult to accurately divide the substrate base material, while the strip-shaped removal regions in the optical film intersect. It has been found that the sagging is likely to occur in the region to be formed, and it becomes difficult to form the optical film with high accuracy. This problem becomes significant when the thickness of the substrate base material is reduced.

  The present invention has been made in view of such various points, and an object of the present invention is to divide both the substrate base material and the optical film attached to the surface thereof with high accuracy, thereby providing a display device. Is to efficiently and accurately manufacture the device.

  In order to achieve the above object, in the present invention, the speed for removing the optical film is made larger than the speed for dividing the substrate base material.

  Specifically, in the method for manufacturing a display device according to the present invention, a pair of substrate base materials are bonded to each other to form a bonded substrate, and a plurality of pieces are provided between the pair of substrate base materials constituting the bonded substrate. A step of arranging and forming the display medium layer in a matrix, a step of attaching an optical film to the bonded substrate, a step of partially removing the optical film from the surface of the bonded substrate, And a step of dividing the bonded substrate in the removal region where the optical film is removed, and a method of manufacturing a display device that manufactures a plurality of display devices from the bonded substrate, wherein the speed of removing the optical film is , Greater than the speed at which the substrate base material is divided.

  The speed at which the optical film is removed is preferably greater than 300 mm / sec and not greater than 400 mm / sec, and the speed at which the substrate base material is divided is preferably not less than 50 mm / sec and not greater than 300 mm / sec.

  The pair of substrate base materials includes a first substrate base material on which a plurality of array substrates are formed and a second substrate base material on which a plurality of counter substrates are formed, and the thickness of the second substrate base material is It is desirable that it is thinner than the first substrate base material.

  The thickness of the second substrate base material may be 20 μm or more and 300 μm or less.

-Action-
Next, the operation of the present invention will be described.

  In manufacturing a display device, first, a pair of substrate base materials are formed. The pair of substrate base materials includes, for example, a first substrate base material on which a plurality of array substrates are formed and a second substrate base material on which a plurality of counter substrates are formed. The thickness of the second substrate base material is preferably about 20 μm or more and 300 μm or less, for example, and is thinner than the first substrate base material. Accordingly, it is possible to reduce the thickness while maintaining the strength of the entire display device by the array substrate (first substrate base material).

  Thereafter, the first substrate base material and the second substrate base material, which are a pair of substrate base materials, are bonded together to form a bonded substrate. The bonded substrate is formed by arranging a plurality of display medium layers in a matrix between the first substrate base material and the second substrate base material.

  Next, an optical film such as a polarizing plate is bonded to the bonded substrate. Subsequently, the bonded substrate is divided along the removal region from which the optical film has been removed. Thereby, a plurality of display devices are manufactured from the bonded substrate.

  As a result of repeated diligent research by the present inventors, when the speed of removing the optical film is relatively small, the optical film is likely to be chipped, whereas when the speed of dividing the substrate base material is relatively large, It has been found that cracks and cracks are likely to occur in the base material. Therefore, the speed for removing the optical film is set larger than the speed for dividing the substrate base material. For example, the speed at which the optical film is removed is greater than 300 mm / sec and not greater than 400 mm / sec, while the speed at which the substrate base material is divided is preferably not less than 50 mm / sec and not greater than 300 mm / sec.

  That is, if the speed at which the optical film is removed is 300 / sec or less, a large chip tends to occur in the optical film. On the other hand, when the removal speed of the optical film is higher than 400 mm / sec, the removal speed is too high, and it becomes difficult to remove the optical film with high accuracy in a predetermined region. Therefore, as described above, the speed at which the optical film is removed is preferably greater than 300 mm / sec and not greater than 400 mm / sec.

  Further, if the speed at which the substrate base material is divided is greater than 300 μm, cracks and cracks are likely to occur in the substrate base material. On the other hand, when the speed at which the substrate base material is divided is less than 50 mm / sec, the productivity of the display device becomes too low. Therefore, as described above, the speed at which the substrate base material is divided is preferably 50 mm / sec or more and 300 mm / sec or less. By doing so, the display device can be manufactured with high accuracy and efficiency.

  According to the present invention, since the speed for removing the optical film is larger than the speed for dividing the substrate base material, the optical film is prevented from being chipped and the substrate base material is prevented from being cracked or cracked. It can be manufactured with high accuracy and efficiency.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the following embodiment.

Embodiment 1 of the Invention
1 to 7 show Embodiment 1 of the present invention. FIG. 1 is a cross-sectional view showing a liquid crystal display device 1 which is a display device of the present embodiment.

  As shown in FIG. 1, the liquid crystal display device 1 includes an array substrate 11, a counter substrate 12 disposed to face the array substrate 11, and a display medium layer interposed between the array substrate 11 and the counter substrate 12. A certain liquid crystal layer 13. The liquid crystal layer 13 is sealed by a seal member 14 formed in a substantially rectangular frame shape between the array substrate 11 and the counter substrate 12.

  The array substrate 11 includes a glass substrate 21 and TFTs (Thin-Film Transistors) (not shown) which are a plurality of active elements formed on the surface of the glass substrate 21 on the liquid crystal layer 13 side. Although not shown, the glass substrate 21 is provided with a pixel electrode, a gate wiring, and a source wiring connected to the TFT. The TFTs and the pixel electrodes are arranged in a matrix on the glass substrate 21, and the gate wirings and the source wirings are arranged so as to be orthogonal to each other and are formed in a lattice shape as a whole. A polarizing plate 23 that is an optical film is attached to the surface of the glass substrate 21 opposite to the liquid crystal layer 13.

  On the other hand, the counter substrate 12 includes a glass substrate 22 and a transparent electrode and a color filter (both not shown) formed on the surface of the glass substrate 22 on the liquid crystal layer 13 side. A polarizing plate 24 that is an optical film is attached to the surface of the glass substrate 22 opposite to the liquid crystal layer 13. The absorption axis of the polarizing plate 24 is orthogonal to the absorption axis of the polarizing plate 23. The counter substrate 12 is formed thinner than the array substrate 11.

  Although not shown, the array substrate 11 is provided with drivers (gate drivers and source drivers) for driving the TFTs, and the TFTs are connected to the TFTs via the gate lines and source lines. By supplying a signal to the pixel electrode, the pixel electrode is driven for each TFT to perform a desired display.

-Manufacturing method-
Next, a method for manufacturing the liquid crystal display device 1 will be described with reference to FIGS. 2 is a cross-sectional view showing the second substrate base material 32 that has been subjected to the removal step and the dividing step (corresponding to FIG. 4), and FIGS. 3 to 5 show that at least one of the removing step and the dividing step is performed. It is a top view which shows the 2nd board | substrate base material 32 to be called. FIG. 6 is a plan view showing the divided second substrate base material 32.

  In this embodiment, the liquid crystal display device 1 is formed from the bonded substrate 30 by dividing the bonded substrate 30 on which the pair of substrate base materials 31 and 32 are bonded. That is, the manufacturing method of the present embodiment includes a bonded substrate forming step, a film sticking step, a removing step, and a dividing step.

  First, a first substrate base material 31 having a plurality of array substrates 11 and a second substrate base material 32 having a plurality of counter substrates 12 are formed in advance. The array substrate 11 is arranged in a matrix on the first substrate base material 31. The counter substrate 12 is arranged in a matrix on the second substrate base material 32 so as to correspond to the array substrate 11. On each array substrate 11, a TFT, a pixel electrode, a gate wiring, a source wiring, and the like are formed.

  3 to 6, the number of liquid crystal display devices 1 included in the first substrate base material 31 (or the second substrate base material 32) is reduced to, for example, four to simplify the description. However, in reality, a larger number of liquid crystal display devices 1 are included.

  Next, in the bonded substrate forming step, the first substrate base material 31 and the second substrate base material 32, which are a pair of substrate base materials, are bonded together to form the bonded substrate 30, and the bonded substrate 30 is A plurality of liquid crystal layers 13 which are display medium layers are arranged in a matrix between the first substrate base material 31 and the second substrate base material 32 to be formed.

  After performing the etching process, it is difficult to inject and enclose liquid crystal. In this embodiment, a liquid crystal display device is manufactured by a so-called liquid crystal dropping method. First, as shown in the flowchart of FIG. 7, in step S <b> 1, for example, a sealing member made of, for example, ultraviolet / heat combination curable resin is provided on at least one of the array substrate 11 and the counter substrate 12 so as to be drawn in a ring shape. . Subsequently, in step S2, liquid crystal is dropped inside the annular seal member. At this time, for example, an annular seal member is formed on the first substrate base material 31, while the region in the second substrate base material 32 corresponds to the region surrounded by the seal member of the first substrate base material 31. In addition, the liquid crystal may be dropped. Thereafter, in step S <b> 3, the first substrate base material 31 and the second substrate base material 32 are bonded together to form a bonded substrate 30. Subsequently, in steps S4 and S5, the seal member is cured by irradiation with ultraviolet rays, heating, or the like.

  Next, in step S6, the surface of the bonded substrate 30 (that is, at least one of the first substrate base material 31 and the second substrate base material 32) is etched to reduce its thickness. Etching is preferably performed in the state of the bonded substrate 30. For example, when the initial thicknesses of the first substrate base material 31 and the second substrate base material 32 are the same, bonding is performed with the resist uniformly applied to the outer surface of the second substrate base material 32. The entire substrate 30 is immersed in the etching solution. Accordingly, the etching amount of the second substrate base material 32 is made larger than that of the first substrate base material 31, and the second substrate base material 32 is made thinner than the first substrate base material 31. And the thickness of the 2nd board | substrate base material 32 shall be 300 micrometers, for example.

  The thickness of the second substrate base material 32 (that is, the counter substrate) is preferably 20 μm or more and 300 μm or less. That is, in order to make the entire liquid crystal display device thin, it is preferable to make the second substrate base material 32 thin. However, if the second substrate base material 32 is less than 20 μm, the strength of the substrate cannot be sufficiently maintained, It becomes difficult to form the second substrate base material 32 itself. On the other hand, if the thickness of the second substrate base material 32 exceeds 300 μm, the thickness of the second substrate base material 32 becomes relatively large, and the problems of cracks and cracks in the glass substrates 21 and 22 are less likely to occur. Therefore, the present invention has a particularly preferable effect when the thickness of the second substrate base material 32 is 20 μm or more and 300 μm or less.

  Next, in step S7, a film sticking process is performed, and the polarizing plates 23 and 24, which are optical films, are placed on both surfaces of the laminated substrate 30 (that is, the outer surfaces of the first substrate base material 31 and the second substrate base material 32). )

  Then, a removal process is performed and the polarizing plates 23 and 24 are partially removed from the surface of the bonding substrate 30. Subsequently, in step S8, a cutting step is performed, and the bonded substrate 30 is cut in the removed region where the polarizing plates 23 and 24 are removed.

  The speed Vh for removing the polarizing plate 23 is set larger than the speed Vk for dividing the first substrate base material 31. Similarly, the speed Vh for removing the polarizing plate 24 is set larger than the speed Vk for dividing the second substrate base material 32. That is, the speed Vh for removing the polarizing plates 23 and 24 is greater than 300 mm / sec and not greater than 400 mm / sec (300 mm / sec <Vh ≦ 400 mm / sec), and the first substrate preform 31 and the second substrate preform. The speed Vk at which the material 32 is divided is set to 50 mm / sec or more and 300 mm / sec or less (50 mm / sec ≦ Vk ≦ 300 mm / sec).

The removal speed Vh is further set to 320 mm / sec <Vh ≦ 380 mm / sec.
It is preferable that the dividing speed Vk is further preferably 70 mm / sec ≦ Vk ≦ 280 mm / sec.

As shown in FIG. 2, the polarizing plates 23 and 24 are removed by a blade 36 attached to a header 35 that can move in parallel with the bonded substrate 30. The blade 36 has, for example, a blade having a U-shaped section or a recessed section. In FIG. 2, the second substrate base material 32 is shown in an enlarged manner for the sake of explanation, and the first substrate base material 31 and the like are not shown. On the other hand, the division of the laminated substrate 30 (that is, the division of the first substrate base material 31 and the second substrate base material 32) is performed by a wheel 38 attached to a header 37 that can move in parallel to the laminated substrate 30. Do. The contact pressure of the blade 36 and the wheel 38 with respect to the first substrate base material 31 and the second substrate base material 32 is desirably 600 g / cm ² or less, for example.

  Then, after one of the first substrate base material 31 and the second substrate base material 32 is divided, the other is divided. Then, the bonded substrate board 30 is divided as a whole by dividing both the first substrate base material 31 and the second substrate base material 32.

  In the case of dividing the second substrate base material 32, first, a removal process is performed as shown in FIG. 3, and the cutting tool 36 is horizontally placed on the second substrate base material 32 as shown by the solid line arrow A1 in FIG. The polarizing plate 24 is partially removed in a strip shape by moving in the direction A1 to form a removal region J1. In the removal region J1, the glass substrate 22 is exposed.

  Next, as shown by a solid arrow A2 in FIG. 4, the polarizing plate 24 is removed in a strip shape by moving the blade 36 in the vertical direction A2 orthogonal to the horizontal direction A1, and the glass substrate 22 is exposed. A removal region J2 is formed. The removal region J2 is formed so as to intersect with the removal region J1.

  Subsequently, a cutting step is performed, and the glass substrate 22 exposed in the removal region J2 is moved by moving the wheel 38 in the same direction B1 as the vertical direction A2 as shown by the broken arrow B1 in FIG. Cut along the length direction of the removal region J2. At this time, the wheel 38 follows the blade 36 moving in the vertical direction A2 and moves in the vertical direction B1. That is, in the process shown in FIG. 4, the removing process and the dividing process are performed simultaneously.

  Thereafter, a removal process is performed as shown in FIG. 5, and the wheel 38 is moved in the lateral direction B2 orthogonal to the longitudinal direction B1 as shown by the broken arrow B2 in FIG. The glass substrate 22 is cut along the removal region J2. As a result, as shown in FIG. 6, the second substrate base material 32 is divided into, for example, four product sizes, and the counter substrate 12 constituting the liquid crystal display device 1 is formed.

  When the first substrate base material 31 is divided, the same process as the above-described division of the second substrate base material 32 is performed. As a result, the first substrate base material 31 is divided into, for example, four product sizes, whereby the array substrate 11 is formed, and, for example, four liquid crystal display devices 1 are formed from the bonded substrate 30.

-Effect of Embodiment 1-
Therefore, according to the first embodiment, the thickness of the second substrate base material 32 is set to be 20 μm or more and 300 μm or less, for example, so as to be thinner than the first substrate base material 31. The thickness can be reduced while maintaining the substrate 11 (first substrate base material 31). In addition, since the speed of removing the polarizing plates 23 and 24 is set higher than the speed of dividing the first and second substrate base materials 31 and 32, the first polarizing plate 23 and 24 are prevented from being chipped and the first is removed. In addition, the liquid crystal display device 1 can be manufactured with high accuracy and efficiency by preventing the second substrate base materials 31 and 32 from being cracked or broken.

  By the way, if the speed Vh for removing the polarizing plates 23 and 24 is 300 mm / sec or less, the polarizing plates 23 and 24 are likely to be largely chipped. On the other hand, when the speed Vh for removing the polarizing plates 23 and 24 is higher than 400 mm / sec, the removing speed Vh is too high, and it becomes difficult to remove the polarizing plates 23 and 24 with high accuracy in a predetermined region.

  On the other hand, in the present embodiment, the speed Vh for removing the polarizing plates 23 and 24 is set to be larger than 300 mm / sec and not more than 400 mm / sec. The polarizing plates 23 and 24 can be accurately removed along the removal regions J1 and J2.

  If the speed Vk at which the first and second substrate base materials 31 and 32 are divided is greater than 300 mm / sec, cracks and cracks are likely to occur in the first and second substrate base materials 31 and 32. turn into. On the other hand, when the speed Vk for dividing the first and second substrate base materials 31 and 32 is less than 50 mm / sec, the productivity of the liquid crystal display device 1 is too low.

  On the other hand, in this embodiment, since the speed Vk for dividing the first and second substrate base materials 31 and 32 is set to 50 mm / sec or more and 300 mm / sec or less, the first and second substrate base materials 31, It is possible to prevent the occurrence of cracks and cracks in the liquid crystal display 32 and to suppress the decrease in productivity of the liquid crystal display device 1.

  That is, according to the present embodiment, the speed Vh for removing the polarizing plates 23 and 24 and the speed Vk for dividing the first and second substrate base materials 31 and 32 are defined within predetermined numerical ranges, respectively. In addition, the liquid crystal display device 1 can be manufactured with high accuracy and efficiency by preventing the polarizing plates 23 and 24 from being cracked and preventing the first and second substrate base materials 31 and 32 from cracking.

  Further, when the polarizing plates 23 and 24 are to be removed so as to straddle the regions already divided in the first and second substrate base materials 31 and 32, the blade 36 is formed on the first and second substrate base materials 31 and 32. Since it becomes easy to catch on a cutting part, it becomes difficult to remove polarizing plates 23 and 24 with sufficient accuracy. In contrast, in the present embodiment, the first and second substrate base materials 31 and 32 are divided after the removal regions J1 and J2 that intersect with each other are formed. , 24 can be removed. Furthermore, as shown in FIG. 4, since the removing process of the polarizing plates 23 and 24 in the vertical direction A2 and the dividing process of the second substrate base material 32 in the vertical direction B1 are continuously performed as the same process, It can be manufactured efficiently with improved tact time.

<< Other Embodiments >>
In the first embodiment, the liquid crystal display device is described as an example of the display device. However, the present invention is not limited to this, and can be similarly applied to other display devices such as an organic EL display device. is there. Moreover, although the polarizing plates 23 and 24 have been described as examples of the optical film, the present invention is not limited to this, and other optical films such as a diffusion film that diffuses light can be applied.

  As described above, the present invention is useful for a method of manufacturing a display device such as a liquid crystal display device, and in particular, accurately divides both the substrate base material and the optical film attached to the surface thereof. Therefore, it is suitable for manufacturing a display device efficiently and with high accuracy.

It is sectional drawing which shows the structure of a liquid crystal display device. It is sectional drawing which shows the 2nd board | substrate base material with which the removal process and the cutting process are performed. It is a top view which shows the 2nd board | substrate base material in which the removal process was performed. It is a top view which shows the 2nd board | substrate base material with which the removal process and the cutting process were performed. It is a top view which shows the 2nd board | substrate base material with which the cutting process was performed. It is a top view which shows the liquid crystal display device formed by dividing a 2nd board | substrate base material into plurality. It is a flowchart which shows the manufacturing process of a liquid crystal display device. It is a perspective view explaining the manufacturing method of the conventional liquid crystal display device. It is a perspective view explaining the manufacturing method of the conventional liquid crystal display device.

Explanation of symbols

J1, J2 removal area 1 liquid crystal display device 11 array substrate 12 counter substrate 13 liquid crystal layer (display medium layer)
23, 24 Polarizing plate (optical film)
30 Lamination board 31 1st board | substrate base material 32 2nd board | substrate base material

Claims (4)

A step of bonding a pair of substrate base materials together to form a bonded substrate, and forming a plurality of display medium layers in a matrix between the pair of substrate base materials constituting the bonded substrate; and ,
A step of attaching an optical film to the bonded substrate;
Partially removing the optical film from the surface of the bonded substrate;
A step of dividing the bonded substrate in the removal region from which the optical film has been removed, and a manufacturing method of a display device for manufacturing a plurality of display devices from the bonded substrate,
The method for manufacturing a display device, wherein a speed at which the optical film is removed is higher than a speed at which the substrate base material is divided. In claim 1,
The speed at which the optical film is removed is greater than 300 mm / sec and not greater than 400 mm / sec,
A method of manufacturing a display device, wherein a speed at which the substrate base material is divided is 50 mm / sec or more and 300 mm / sec or less. In claim 1,
The pair of substrate base materials includes a first substrate base material on which a plurality of array substrates are formed and a second substrate base material on which a plurality of counter substrates are formed,
The method for manufacturing a display device, wherein the thickness of the second substrate base material is thinner than that of the first substrate base material. In claim 3,
The thickness of the second substrate base material is 20 μm or more and 300 μm or less.

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