JP2010224110A - Method for manufacturing plastic liquid crystal panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bending method that does not cause the occurrence of cracks and exfoliation in the transparent electrode film of a plastic liquid crystal panel. <P>SOLUTION: The method includes a step of preparing a plastic liquid crystal cell 10 including a plastic substrate having a transparent electrode film in an amorphous state, a step of bending the plastic liquid crystal cell 10, a step of heating the plastic liquid crystal cell 10 while bending it, and a step of crystallization of the transparent electrode film in the amorphous state. The step of heating the plastic liquid crystal cell while bending it and the step of crystallization of the transparent electrode film in the amorphous state may be simultaneously performed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a liquid crystal panel using a plastic plate or a plastic film as a substrate.

  As a conventional method of manufacturing a curved liquid crystal panel, a method of bending along a direction strong against bending peeling of wiring electrodes is known. (For example, refer to Patent Document 1).

  The liquid crystal display device disclosed in Patent Document 1 will be described with reference to FIG. FIG. 5 is a schematic diagram for explaining the operation of the conventional liquid crystal display device. First, as shown in FIG. 5, when the electrode wiring is configured by the configuration of the prior art, the direction of the vertical wiring 52 along the direction of the vertical wiring 50 is curved along the direction of the horizontal wiring 51. From the experimental result that the peeling is less than the bending in the direction of the lateral direction 53, the bending direction in which the wiring electrode is less likely to be peeled off or cracked is defined. As described above, in the conventional example, the liquid crystal display device is curved in consideration of the direction in which peeling does not easily occur even if the wiring electrode is curved due to the material, thickness, width, and the like.

  Although not shown, as another conventional example, an insulating resin film is further formed on the conductive film formed on the substrate to relieve the stress on the conductive film generated when the liquid crystal panel is bent. Some examples suggest a structure. (For example, refer to Patent Document 2).

Japanese Patent No. 3238223 (FIG. 1) Japanese Patent No. 3427729

  Generally, in order to bend a plastic plate, heating and pressing are performed. However, when this method is applied to a plastic liquid crystal panel, the transparent electrode film is disconnected, causing a display defect, which causes a decrease in yield and has not been used practically.

  In the method described in Patent Document 1, the bending direction is determined, and there is no degree of freedom in designing the substrate. Therefore, even if bending in only one direction can be handled, the design of the electrode wiring on the board becomes complicated and bending into a free shape when bending at two or more locations with one liquid crystal panel. It was difficult.

  In the method described in Patent Document 2, it is necessary to apply a protective film on the transparent electrode, the layer structure of the substrate is increased, and the electrode is separated from the liquid crystal layer. Therefore, it is necessary to set the driving voltage high. However, it is not suitable for a structure with low cost and low power consumption.

  As is apparent from the above, the conventional method for manufacturing a liquid crystal display device has a problem that it can cope with bending into any shape and cannot make a low-cost liquid crystal display device. SUMMARY OF THE INVENTION Accordingly, the object of the present invention is to solve the above-mentioned problems, and to provide a manufacturing method which can deal with bending work at a plurality of locations, with a simple substrate layer structure, no restrictions on electrode wiring design.

In order to solve the above-described problems, the plastic liquid crystal panel manufacturing method of the present invention employs the following constituent elements.

  The method for producing a plastic liquid crystal panel according to the present invention includes a step of preparing a plastic liquid crystal cell including a plastic substrate having a transparent electrode film in an amorphous state, a step of bending the plastic liquid crystal cell, and heating while curving the plastic liquid crystal cell. And a step of crystallizing the transparent electrode film in an amorphous state. The transparent electrode film is preferably indium tin oxide.

By adopting the production method of the present invention, the liquid crystal panel can be bent without causing peeling or cracking in the electrode wiring.

It is sectional drawing which shows the structure of the plastic liquid crystal panel to which the manufacturing method of this invention is applied. It is sectional drawing which showed the process of the bending process in the manufacturing method of this invention. It is a 1st figure for demonstrating the heating temperature in FIG. It is a 2nd figure for demonstrating the heating temperature in FIG. It is a wiring pattern figure which shows the conditions of the bending process of the conventional prior art example.

  An embodiment of a method for producing a plastic liquid crystal panel of the present invention will be described below with reference to the drawings.

  First, FIG. 1 is a cross-sectional view showing a configuration of a plastic liquid crystal cell used in this embodiment. As shown in FIG. 1, the plastic liquid crystal cell 10 uses a plate material in which an amorphous transparent electrode film 12 is formed on one surface of a substrate 11 made of a plastic plate or plastic film. Further, two plate members are used and the liquid crystal 13 is sandwiched.

  Further, the liquid crystal 13 is sealed with a sealing material 14 so as not to protrude. Some plastic liquid crystal cells 10 have a structure in which spacers 15 are arranged in order to keep the gap between the upper and lower substrates constant.

Next, a method for manufacturing a plastic liquid crystal cell will be described.
First, a plastic liquid crystal cell including a plastic substrate having an amorphous transparent electrode film is prepared.
Next, the process of bending the plastic liquid crystal panel of this embodiment will be described with reference to FIG. First, as shown in FIG. 2A, the plastic liquid crystal cell 10 is sandwiched between molds 20 processed into a shape to be deformed. The mold 20 can be pressurized by hydraulic pressure or air pressure, and the plastic liquid crystal cell may be bent along the shape of the mold 20.

Next, as shown in FIG. 2B, the mold 20 is heated by the heater 21, and the plastic liquid crystal cell 10 is heated while being bent into the shape of the mold 20. In this embodiment, heating is performed using the heater 21 disposed on the mold 20, but the mold 20 with the plastic liquid crystal cell 10 interposed therebetween may be heated in the furnace. The optimum heating temperature is determined by the heat resistance temperature of the substrate material. For example, when the substrate material is polycarbonate, since the softening temperature is around 140 to 145 ° C. and the melting point is around 220 to 230 ° C., the heating temperature is set between 140 and 230 ° C. If it is too close to the melting point, the substrate material melts and deformation becomes too large, and the transparent electrode film 12 formed on the surface may be broken. Therefore, it is preferable to set the temperature between the softening temperature and the melting point as low as possible. . By this step, the transparent electrode film 12 is crystallized. The setting of the heating temperature will be described in detail later with reference to FIGS.

  When the heating step is completed and the mold 20 is removed, a curved plastic liquid crystal panel 10 ′ can be obtained in a shape along the shape of the mold 20 as shown in FIG.

Next, setting of the heating temperature will be described with reference to FIGS. FIG. 3A is a diagram showing an analysis result of X-ray diffraction performed on the transparent electrode film 12 on the plastic substrate 11 used in the present invention. As the plastic substrate 11, a polycarbonate substrate is used, and the state of crystallization of indium tin oxide which is the transparent electrode film 12 formed thereon is shown. The measured sample is in a state of being stored at room temperature after forming an indium tin oxide film by low-temperature sputtering. If crystallized, the crystal peak of InO ₂ appears in the vicinity of 30 deg as shown in FIG. 4b described later, but there is no peak in FIG. 3A, and it can be seen that the film of indium tin oxide is in an amorphous state. . Generally, in order to form a thin film of indium tin oxide on a plastic substrate, it is formed by a low-temperature sputtering method because the heat-resistant temperature of the substrate is low. In this case, the thin film of indium tin oxide is in an amorphous state without being crystallized.

  Next, FIG. 3B shows the result of X-ray diffraction measurement after heating this sample at 60 ° C. for 3 hours. When heating at 60 ° C. for 3 hours, a peak indicating crystallization still does not appear, indicating that the film is still in an amorphous state. That is, it indicates that it does not crystallize when stored near room temperature.

  Next, FIG. 4A shows the result of X-ray diffraction measurement of the state of crystallization by further heating this sample at 110 ° C. for 3 hours. Even in this state, a peak indicating crystallization does not appear, and it can be seen that an amorphous state is obtained even at 110 ° C.

  Furthermore, the result at the time of heating at 120 degreeC for 3 hours at FIG.4 (b) is shown. As shown in FIG. 4B, a crystal peak indicating crystallization of InO 2 appears in the vicinity of 30 deg, indicating that crystallization has occurred.

  That is, it can be seen that the film of indium tin oxide on the plastic substrate 11 used in this example does not crystallize unless heated at 120 ° C. or higher. In general, when a film is crystallized, when bending stress is applied, the film is increased in hardness due to the formation of crystals or cracks are generated at the crystal interface, and the film tends to become brittle when crystallized. In the amorphous state, since there is no crystal, the film is soft and hardly cracked.

  Therefore, the step of heating while curving in this example is performed before the transparent electrode film is exposed to a temperature of 120 ° C. or higher, and the transparent electrode film prepared before that step is in an amorphous state. Even when the plastic liquid crystal cell is deformed along the mold in the step of heating while being bent as shown in FIG. 2, the transparent electrode film can be bent without causing defects such as peeling or cracking.

  Since the temperature at which the substrate material and the transparent electrode film are formed changes to the amorphous state, the temperature condition for crystallization from the amorphous state first measures the crystallization state, such as X-ray diffraction, and determines the timing of the overheating process. There is a need to. In any case, it is necessary to perform bending when the transparent electrode film is in an amorphous state.

As long as the transparent electrode is in an amorphous state, cracks do not occur in any direction, so there is no direction in which the transparent electrode cannot be bent depending on the direction of the wiring pattern as shown in the conventional example. For this reason, there are no restrictions on the direction of bending, so various shapes can be handled. In addition, since it is not necessary to form a protective film or the like on the wiring pattern as in the conventional example, the structure of the plastic liquid crystal panel becomes simple and can be manufactured at low cost.
Moreover, according to the manufacturing method of this embodiment, even if a plurality of bending processes are performed on one liquid crystal cell, the transparent electrode is not cracked or peeled off.

  As is clear from the above description, the plastic liquid crystal panel manufacturing method of the present embodiment can solve the problems of the conventional example and provide a plastic liquid crystal panel that is curved into various shapes.

  Furthermore, since a protective film or the like is not required and the layer structure is simple compared to the conventional example, it is not necessary to change the structure of the plastic liquid crystal panel specially for bending. Therefore, the plastic liquid crystal panel can be bent at a low cost.

  Thus, a plastic liquid crystal panel subjected to various bending processes can be manufactured, and a curved display body can be provided with a high yield and a low cost.

DESCRIPTION OF SYMBOLS 10 Plastic liquid crystal panel 11 Board | substrate 12 Transparent electrode film 13 Liquid crystal 14 Sealing material 15 Spacer 20 Type 21 Heater 50 Vertical wiring 51 Horizontal wiring 52 Vertical direction 53 Horizontal direction

Claims (2)

Preparing a plastic liquid crystal cell including a plastic substrate having an amorphous transparent electrode film;
Bending the plastic liquid crystal cell;
Heating the plastic liquid crystal cell while curving it, and crystallizing the amorphous transparent electrode film.   The method for producing a plastic liquid crystal panel according to claim 1, wherein the transparent electrode film is indium tin oxide.

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