JP2013182170A - Liquid crystal display element and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a liquid crystal display element, capable of sticking a color filter even to a liquid crystal cell with low transmissivity at an OFF voltage.SOLUTION: (a) A liquid crystal cell where a plurality of alignment marks are formed is prepared, a first reference point is calculated on the basis of the alignment mark of the liquid crystal cell, a sheet with a color filter where a plurality of alignment marks are formed is prepared, and a second reference point is calculated on the basis of the alignment mark of the sheet with the color filter. (b) The liquid crystal cell and the sheet with the color filter are stuck so as to overlap the first reference point and the second reference point when viewed from a normal direction of the liquid crystal cell.

Description

  The present invention relates to a liquid crystal display element and a manufacturing method thereof, and more particularly to a liquid crystal display element including a color filter and a manufacturing method thereof.

  For example, when assembling a plurality of members, it is widely performed that an alignment mark is formed on each member for alignment.

  For example, an alignment mark is formed on each of two substrates, and a difference in light intensity between reflected light from one mark and reflected light from an overlapping portion of both marks is detected. An invention of an alignment method that detects a relative position and aligns two substrates based on a detection result is disclosed (for example, see Patent Document 1). According to the method described in Patent Document 1, it is possible to align two substrates with high accuracy.

  The structure of the liquid crystal display device is characterized in that an alignment mark is formed on both the liquid crystal display board and the circuit board, and further, a confirmation window and a daylighting hole are provided to enable confirmation of the alignment mark from the outside of the liquid crystal display device. The invention which concerns is disclosed (for example, refer patent document 2). According to the invention described in Patent Document 2, it is only necessary to confirm the position of the alignment mark from the confirmation window at the time of assembly, so that the liquid crystal display panel and the circuit board can be easily aligned.

  As described in Patent Documents 1 and 2, generally, alignment is performed by overlapping alignment marks formed on a plurality of members.

  An internal color type liquid crystal display element in which a color filter is disposed inside a liquid crystal cell is known.

  FIG. 2A is a schematic cross-sectional view of the inner color type liquid crystal display element. The inner color type liquid crystal display element includes an upper substrate 10a, a lower substrate 10b, and a liquid crystal layer 15 disposed therebetween. The upper substrate 10a includes a transparent substrate, for example, a glass substrate 11a, and a transparent electrode 12a formed of ITO on the glass substrate 11a. The lower substrate 10b includes, for example, a glass substrate 11b, a color filter layer 13 formed on the glass substrate 11b, a planarization layer 14 formed so as to cover the glass substrate 11b and the color filter layer 13, and a planarization layer 14 The transparent electrode 12b formed above is provided. In addition, description of the alignment film was abbreviate | omitted.

  In the inner surface color type liquid crystal display element, the color filter layer 13 is formed in the liquid crystal cell with high positional accuracy, for example, with high positional accuracy such as an error range of several μm to several tens of μm. However, the inner color type liquid crystal display element is expensive.

  An external color type liquid crystal display element is also known.

  FIG. 2B is a schematic perspective view showing a manufacturing method of the outer color type liquid crystal display element. A sheet material 23 having a color printing portion 24 is attached to the lower substrate 20b side of the liquid crystal cell 22 including the upper substrate 20a and the lower substrate 20b. The upper substrate 20a and the lower substrate 20b each include a glass substrate and a transparent electrode formed thereon. A liquid crystal layer is disposed between the transparent electrodes. An alignment mark 21 is formed on the glass substrate of the upper substrate 20a. The sheet material 23 is, for example, a diffusing material or a reflecting material, and an alignment mark 25 is formed on the sheet material 23. The sheet material 23 has, for example, a size in a range where the upper substrate 20a and the lower substrate 20b overlap, and is attached to the range. A polarizing plate is disposed on each of the upper substrate 20a and lower substrate 20b surfaces.

  When the sheet material 23 is attached to the liquid crystal cell 22, alignment is performed so that the alignment mark 21 and the alignment mark 25 overlap each other.

  The liquid crystal display element of the outer color type can be manufactured at a low cost. However, there is a problem that the positional accuracy is not so high. For example, since the variation in the outer shape of the sheet material 23 is about ± 0.2 mm, the variation in the color printing position is about the same amount of about ± 0.2 mm. Further, when the sheet material 23 is applied to the liquid crystal cell 22, Since the deviation occurs about ± 0.3 mm to ± 0.5 mm, the total deviation amount of the color printing portion (color filter) 24 is about ± 0.5 mm to ± 0.7 mm. Therefore, it cannot be said that it is suitable for a liquid crystal display element that displays a design with a small gap between display patterns.

Japanese Patent Application Laid-Open No. 60-110119 Japanese Patent Laid-Open No. 7-13133

  The outer color type liquid crystal display element also has a problem with the alignment itself in the manufacturing process. For example, for a liquid crystal cell having a very low transmittance at the off voltage, such as a vertically aligned negative liquid crystal cell, it is difficult to detect alignment marks and confirm alignment mark overlap.

  FIG. 2C shows one way to solve this problem. For example, the size of the sheet material 23 may be expanded to a size equal to the size of the lower substrate 20b, and the positions of the alignment marks 21 and 25 may be changed. The alignment mark 21 on the liquid crystal cell 22 side is formed on the lower substrate 20b. The alignment mark 25 on the sheet material 23 side is formed in the extended portion. As a result, even for a liquid crystal display element having a very low transmittance at the off voltage, the alignment between the alignment mark 21 and the alignment mark 25 can be performed to align the liquid crystal cell 22 and the sheet material 23. However, this method impairs the durability and appearance (look) of the liquid crystal display element.

  An object of the present invention is to provide a method for manufacturing a liquid crystal display element capable of attaching a color filter to a liquid crystal cell having a low transmittance at the time of off-voltage, such as a vertically aligned negative liquid crystal cell, and the manufacturing method It is providing the liquid crystal display element manufactured by this.

  According to one aspect of the present invention, (a) preparing a liquid crystal cell in which a plurality of alignment marks are formed, calculating a first reference point based on the alignment marks of the liquid crystal cell, and forming a plurality of alignment marks Preparing a color filter-attached sheet and calculating a second reference point based on an alignment mark of the color filter-attached sheet; and (b) when viewed from the normal direction of the liquid crystal cell, There is provided a method for manufacturing a liquid crystal display element, which includes a step of attaching the liquid crystal cell and the sheet with the color filter so that the reference point overlaps the second reference point.

  Further, according to another aspect of the present invention, the liquid crystal cell having the first alignment mark formed thereon, and the sheet with the color filter attached to the liquid crystal cell and having the second alignment mark formed thereon, When viewed from the normal direction of the liquid crystal cell, a liquid crystal display element in which the first alignment mark and the second alignment mark do not overlap is provided.

  According to the present invention, a method for manufacturing a liquid crystal display element capable of attaching a color filter to a liquid crystal cell having a low transmittance at off voltage, and a liquid crystal display element manufactured by the manufacturing method are provided. Can be provided.

1A is a flowchart showing a method for manufacturing a liquid crystal display element according to an embodiment, FIG. 1B is a perspective view schematically showing a method for manufacturing a liquid crystal display element according to the embodiment, and FIG. 1C is a liquid crystal display according to the embodiment. It is a schematic sectional drawing which shows the liquid crystal display element manufactured with the manufacturing method of an element. 2A is a schematic cross-sectional view of an inner color type liquid crystal display element, FIG. 2B is a schematic perspective view showing a manufacturing method of the outer color type liquid crystal display element, and FIG. 2C is an outer color type liquid crystal display element. It is a schematic perspective view which shows one method of solving the problem of the alignment in the manufacturing process of a display element.

  With reference to FIGS. 1A to 1C, a method of manufacturing a liquid crystal display device according to an embodiment will be described. The manufacturing method of the liquid crystal display element according to the embodiment is a method of manufacturing a liquid crystal display element by attaching a color filter to a liquid crystal cell having a low off-voltage transmittance, for example, a vertically aligned negative liquid crystal cell.

  FIG. 1A is a flowchart illustrating a method for manufacturing a liquid crystal display device according to an embodiment. In the embodiment, first, in step S101, a liquid crystal cell in which two or more alignment marks are formed is prepared, and the alignment marks are image-recognized. Then, a virtual reference point is calculated from the image recognition result.

  Next, the same operation is performed on the sheet with the color filter. That is, in step S102, a sheet with a color filter on which two or more alignment marks are formed is prepared, and the alignment marks are image-recognized. Then, a virtual reference point is calculated from the image recognition result.

  And a liquid crystal cell and a sheet | seat with a color filter are stuck using the equipment provided with an actuator function, for example so that the virtual reference point calculated by step S101 and the virtual reference point calculated by step S102 may overlap.

  Note that the order of step S101 and step S102 may be reversed, or may be performed simultaneously.

  FIG. 1B is a perspective view schematically illustrating a method for manufacturing a liquid crystal display element according to an embodiment, and FIG. 1C is a schematic cross-sectional view illustrating a liquid crystal display element manufactured by a method for manufacturing a liquid crystal display element according to the embodiment. is there.

  A sheet material 40 having a color print portion (color filter) 41 is attached to a liquid crystal cell 39 including an upper substrate 30a, a lower substrate 30b, and a liquid crystal layer 31 disposed therebetween. The liquid crystal cell 39 further includes polarizing plates 32a and 32b. Polarizers 32a and 32b are arranged in crossed Nicols on the surfaces of the upper substrate 20a and the lower substrate 20b opposite to the surfaces on which the liquid crystal layer 31 is arranged.

  The upper substrate 30a and the lower substrate 30b are respectively glass substrates (transparent substrates) 36a and 36b, transparent electrodes 37a and 37b formed on the glass substrates 36a and 36b, and glass substrates 36a and 36b and transparent electrodes 37a and 37b. Alignment films 38a and 38b formed to cover the top are included. The liquid crystal layer 31 is disposed between the alignment films 38a and 38b of the upper substrate 30a and the lower substrate 30b.

  Alignment marks 33 and 34 are formed on the glass substrate 36b of the lower substrate 30b. The sheet material 40 is, for example, a diffusing material or a reflecting material, and alignment marks 42 and 43 are formed on the sheet material 40. The sheet material 40 has a size in a range where the upper substrate 30a and the lower substrate 30b overlap, for example, and is affixed on the polarizing plate 32b in the range.

  In pasting, first, the operation of step S101 is performed. That is, image recognition (pattern recognition) is performed on the alignment marks 33 and 34 formed on the lower substrate 30b of the liquid crystal cell 39, and the position of the virtual reference point 35 is calculated based on the recognition result. Subsequently, the operation of step S102 is performed. That is, the alignment marks 42 and 43 formed on the sheet material 40 are image-recognized (pattern recognition), and the position of the virtual reference point 44 is calculated based on the recognition result. Arbitrary positions corresponding to each other between the liquid crystal cell 39 and the sheet material 40 (arbitrary positions that are the same in two dimensions) can be defined as virtual reference points 35 and 44. As an example, the center positions of the pasting ranges on the liquid crystal cell 39 side and the sheet material 40 side can be obtained as virtual reference points 35 and 44, respectively.

  Then, the operation of step S103 is performed. That is, when the virtual reference point 35 defined on the liquid crystal cell 39 side and the virtual reference point 44 defined on the sheet material 40 side are viewed from the normal direction of the substrates 30a and 30b (the normal direction of the liquid crystal cell 39). The liquid crystal cell 39 and the sheet material 40 are bonded so as to overlap each other.

  As shown in FIG. 1C, the liquid crystal display device manufactured using the method for manufacturing a liquid crystal display device according to the embodiment has alignment marks 33 and 34 and alignment marks 42 and 42 when viewed from the normal direction of the substrates 30a and 30b. 43 is a liquid crystal display element that does not overlap with 43.

  In the vertical alignment negative type liquid crystal cell, since the refractive index anisotropy Δn of the liquid crystal material does not occur at the off voltage, the transmittance at the off voltage is in principle a very low value depending on the polarizing plate. For this reason, it is extremely difficult to perform alignment by observing the alignment mark through the liquid crystal cell and overlaying the alignment marks.

  According to the method for manufacturing a liquid crystal display element according to the embodiment, the virtual reference point 35 is calculated based on the alignment marks 33 and 34 formed on the liquid crystal cell 39, and the alignment marks 42 and 43 formed on the sheet material 40 are calculated. Based on this, the virtual reference point 44 is calculated. And since the sheet material 40 is affixed to the liquid crystal cell 39 so that the calculated virtual reference points overlap when viewed from the normal direction of the substrates 30a and 30b, the position of the alignment mark is not observed with the transmitted light. The sheet material 40 (color filter 41) can be pasted together. For this reason, the color filter 41 can be attached to a liquid crystal cell 39 having a low transmittance at the off voltage, such as a vertical alignment negative liquid crystal cell.

  In addition, according to the method for manufacturing a liquid crystal display element according to the embodiment, the sheet material 40 (color) is placed on the liquid crystal cell 39 with higher positional accuracy than, for example, the method for manufacturing an external color liquid crystal display element described with reference to FIG. A filter 41) can be applied. According to the manufacturing method of the liquid crystal display element according to the embodiment, since the image recognition (pattern recognition) is applied, there is no need to consider the variation in the outer shape of the sheet material 40, and the application variation can be greatly reduced. For example, the pasting accuracy using image recognition (pattern recognition) is about ± 0.03 mm, and this is the deviation amount of the color filter 41 as it is.

  Furthermore, a liquid crystal display element with a color filter can be manufactured easily and inexpensively compared to the inner surface color type liquid crystal display element shown in FIG. 2A.

  Further, when compared with the method for manufacturing a liquid crystal display element described with reference to FIG. 2C, the durability and appearance (appearance) of the manufactured liquid crystal display element are not impaired.

  Although the present invention has been described with reference to the embodiments, the present invention is not limited thereto.

  For example, in the embodiment, two alignment marks 33, 34, 42, and 43 are formed on both the liquid crystal cell 39 and the sheet material 40, respectively, but even if three or more alignment marks are formed. Good. When the alignment mark printing accuracy is high, even if there are two alignment marks, alignment can be performed with high accuracy if only the rotation of the liquid crystal cell 39 and the sheet material 40 can be compensated. If the configuration is such that the virtual reference point is calculated using three or more alignment marks, even if the alignment mark printing accuracy is not sufficiently high or the rotation of the liquid crystal cell 39 and the sheet material 40 is not compensated, It is possible to perform highly accurate alignment.

  Further, the liquid crystal display element according to the embodiment is a liquid crystal display element in which the alignment marks 33 and 34 and the alignment marks 42 and 43 do not overlap when viewed from the normal direction of the substrates 30a and 30b. This is because, in the method for manufacturing a liquid crystal display device according to the embodiment, a reference point obtained from the plurality of alignment marks 33 and 34 arranged in the liquid crystal cell 39 and a plurality of alignment marks 42 and 43 arranged on the sheet material 40. This is because alignment is performed using a reference point obtained from the above. That is, the positional relationship between the alignment marks 33 and 34 on the liquid crystal cell 39 side and the alignment marks 42 and 43 on the sheet material 40 side may be arbitrary. In addition, the positional relationship between the alignment marks 33 and 34 and the positional relationship between the alignment marks 42 and 43 may be arbitrary. However, when the liquid crystal display element manufactured by controlling the formation positions of the alignment marks 33, 34, 42, 43 is viewed from the normal direction of the substrates 30a, 30b, the alignment marks 33, 34 and the alignment marks 42, It is also possible to make a liquid crystal display element overlapping with 43. It seems that it is better to overlap the alignment mark on the liquid crystal cell 39 side and the alignment mark on the sheet material 40 side, but if the transmittance at the off-voltage of the liquid crystal cell 39 is low, it overlaps and does not overlap. Is substantially equal in the sense that both alignment marks cannot be observed simultaneously in frontal observation.

  Further, in the examples, a vertically aligned negative type liquid crystal cell is used as a liquid crystal cell having low transmittance at off-voltage and difficult to observe the transmitted light of the alignment mark. For example, the retardation Δnd of the liquid crystal layer is 1. The same effect can be obtained even with a TN (twisted nematic) alignment negative liquid crystal cell in which 827 μm ≦ Δnd ≦ 2.436 μm (avr. 2.2335 μm). Note that the present invention can also be used when a color filter is attached to a liquid crystal cell that does not have a low off-voltage transmittance and allows observation of transmitted light through the alignment mark.

  It will be apparent to those skilled in the art that other various modifications, improvements, combinations, and the like can be made.

  For example, it can be used for manufacturing an outer color type liquid crystal display element (attaching a color filter). Further, the present invention is not limited to the color filter, and can be used for the entire manufacture of liquid crystal display elements having a configuration in which a member is attached (overlaid) outside the liquid crystal cell.

10a Upper substrate 10b Lower substrate 11a, 11b Glass substrate 12a, 12b Transparent electrode 13 Color filter layer 14 Flattening layer 15 Liquid crystal layer 20a Upper substrate 20b Lower substrate 21 Alignment mark 22 Liquid crystal cell 23 Sheet material 24 Color printing portion 25 Alignment Mark 30a Upper substrate 30b Lower substrate 31 Liquid crystal layer 32a, 32b Polarizing plate 33, 34 Alignment mark 35 Virtual reference point 36a, 36b Glass substrate 37a, 37b Transparent electrode 38a, 38b Alignment film 39 Liquid crystal cell 40 Sheet material 41 Color printing part (Color filter)
42, 43 Alignment mark 44 Virtual reference point

Claims (7)

(A) preparing a liquid crystal cell in which a plurality of alignment marks are formed, calculating a first reference point based on the alignment marks of the liquid crystal cell, and preparing a sheet with a color filter in which the plurality of alignment marks are formed And calculating a second reference point based on the alignment mark of the sheet with the color filter;
(B) a step of attaching the liquid crystal cell and the sheet with the color filter so that the first reference point and the second reference point overlap when viewed from the normal direction of the liquid crystal cell; Manufacturing method of liquid crystal display element having   In the step (a), the plurality of alignment marks formed on the liquid crystal cell are image-recognized, the first reference point is calculated based on the recognition result, and the plurality of the alignment marks formed on the sheet with the color filter. 2. The method of manufacturing a liquid crystal display element according to claim 1, wherein the second reference point is calculated based on a recognition result of image recognition of the alignment mark.   The method for manufacturing a liquid crystal display element according to claim 1, wherein the liquid crystal cell is a vertically aligned negative liquid crystal cell.   The method for producing a liquid crystal display element according to claim 1, wherein the liquid crystal cell is a TN alignment negative liquid crystal cell in which a retardation of a liquid crystal layer is 1.827 μm or more and 2.436 μm or less. A liquid crystal cell in which a first alignment mark is formed;
A sheet with a color filter attached to the liquid crystal cell and having a second alignment mark formed thereon;
A liquid crystal display element in which the first alignment mark and the second alignment mark do not overlap when viewed from the normal direction of the liquid crystal cell.   The liquid crystal display element according to claim 5, wherein the liquid crystal cell is a vertically aligned negative liquid crystal cell.   The liquid crystal display element according to claim 5, wherein the liquid crystal cell is a TN alignment negative liquid crystal cell in which the retardation of the liquid crystal layer is 1.827 μm or more and 2.436 μm or less.

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