JP5067862B2 - Liquid crystal display device and manufacturing method thereof - Google Patents

Description

  The present invention relates to a liquid crystal display device including a transparent electrode patterned into a desired shape.

  Conventional liquid crystal cells used in liquid crystal display devices are conventionally manufactured by the following manufacturing method. First, a transparent conductive film such as ITO (Indium Tin Oxide) is vapor-deposited on a glass substrate, and after applying a photoresist, a photomask is set in an exposure machine, and a desired pattern is exposed. After the exposure, the transparent conductive film is processed into a desired electrode pattern by developing, etching, and peeling processes. An alignment film is applied on the ITO film by a flexographic printing machine, an ink jet coating apparatus or the like. Note that an insulating film may be applied before applying the alignment film. Thereafter, the alignment film is rubbed. The two substrates that have been subjected to the rubbing treatment are overlapped so that the alignment films face each other, and a liquid crystal material is injected between the two substrates and sealed, and polarizing plates are attached to both outer side surfaces. This completes the liquid crystal cell.

  Thus, in order to process the transparent conductive film of the liquid crystal cell into a desired electrode pattern, the steps of exposure, development, etching, and peeling are necessary, and the steps are complicated. In addition, it is necessary to manage and replace the chemical solution and to dispose of it, which causes a cost increase. Further, in the exposure process, it is necessary to prepare a photomask for each display pattern in addition to the exposure machine, so that the production and management of the photomask is costly, and the high-mix low-volume production leads to an increase in cost.

In order to solve these problems, a dry etching method has been used instead of the wet etching process. Recently, in order to simplify the process from exposure to peeling, a technique for irradiating a transparent conductive film with laser light and evaporating the transparent conductive film by an ablation action is disclosed in, for example, Patent Documents 1 and 2. Yes.
JP-A-9-152618 JP 7-320637 A

  In a liquid crystal display device, static driving, multiplex (dudy) driving, or the like is used as a driving method. Multiplex drive involves connecting multiple transparent electrodes to one electrode terminal, applying a signal voltage to the transparent electrode on one substrate of the liquid crystal panel, and supplying a scanning voltage to the transparent electrode on the other substrate. This is a method of selecting and displaying transparent electrodes in a series. In this driving method, a predetermined driving voltage higher than the critical voltage is applied to the liquid crystal of the selection electrode, and a predetermined low voltage lower than the critical voltage is applied to the liquid crystal of the non-selection electrode. For this reason, since the liquid crystal molecules rise slightly in the electric field direction even in the non-selected electrode, the display state (transmittance) is slightly different from the region where the electrode is not arranged. For this reason, the non-selected electrode is recognized by the observer, and the display quality is lowered. In addition, the non-selected electrode is more noticeable when viewed from an oblique direction.

  An object of the present invention is to provide a liquid crystal display device in which non-selected electrodes are not easily recognized by an observer.

  In order to achieve the above object, according to the present invention, the following liquid crystal display device is provided. That is, a liquid crystal display device having a pair of transparent substrates disposed opposite to each other, transparent electrodes having predetermined shapes disposed on opposite surfaces of the pair of transparent substrates, and liquid crystal sandwiched between the substrates. Thus, at least one of the pair of transparent substrates is provided with a transparent film having irregularities on the surface in a region where the transparent electrode is not provided. As a result, the alignment state of the liquid crystal molecules is slightly disturbed by the unevenness of the transparent film, and the liquid crystal molecules are close to the alignment state under the electrodes to which a predetermined low voltage is applied. Therefore, an electrode to which a low voltage is applied is not easily recognized by an observer, and display quality is improved.

  As the transparent film having irregularities on the surface, for example, an island-like discontinuous film can be used. Moreover, a transparent film and a transparent electrode can be formed with a transparent conductive film. In this case, the transparent film and the transparent electrode are not in contact with each other.

  Further, the transparent electrode can be configured to selectively apply one of a predetermined selection voltage and a non-selection voltage by multiplex driving. Since the alignment state of the liquid crystal molecules under the transparent electrode to which a non-selection voltage of a predetermined low voltage is applied is close to the alignment state of the liquid crystal molecules under the uneven transparent film, the non-selection electrode is difficult to recognize. Become.

  In addition, according to the present invention, the following method for manufacturing a liquid crystal display device is provided. That is, a method of manufacturing a liquid crystal display device including a substrate having a transparent electrode having a predetermined shape, wherein the transparent conductive film is turned into a transparent electrode having a predetermined shape by irradiating the substrate having the transparent conductive film with laser light. At the same time as the processing, the surface of the transparent conductive film in the peripheral region of the transparent electrode is processed into irregularities. Thereby, the liquid crystal display device by which the transparent conductive film which has an unevenness | corrugation on the surface is arrange | positioned in the area | region around a transparent electrode can be manufactured.

  It is desirable to process the transparent electrode so that it is not in contact with the transparent conductive film in the peripheral region. This is to prevent the drive voltage from being applied to the transparent conductive film in the outer region.

  It is also possible to process the transparent conductive film in the peripheral region of the transparent electrode into an island-like discontinuous film by laser light irradiation. As the laser light, for example, YVO laser light or YAG laser light can be used.

  A liquid crystal display device according to an embodiment of the present invention will be described with reference to the drawings.

  The liquid crystal display device of the present embodiment displays character display or mixed display of character display and dot matrix display by multiplex driving. This liquid crystal display device has a non-display area that does not contribute to display around the display area. In the present embodiment, a non-selective electrode is formed by disposing a transparent film having irregularities on the surface or a discontinuous transparent film in the form of minute islands in a non-display area where a transparent electrode film is not normally disposed. Make it difficult to recognize.

  That is, by arranging a transparent film having an uneven surface or an island shape in a non-display region where no electrode is disposed, the alignment state of liquid crystal molecules in the non-display region is slightly disturbed. The state of this liquid crystal molecule is similar to the state of the liquid crystal molecule under a non-selected electrode to which a predetermined low voltage is applied in the multiplex drive display (a state where it rises slightly in the electric field direction), and the light transmittance is close. Become. Therefore, the non-selection electrode and the non-display region in the display area are almost equal to the viewer's view, and the phenomenon that the non-selection electrode is recognized by the observer can be eliminated, so that the display quality is improved.

  An island-shaped transparent film having an uneven surface or a minute surface can be formed by irradiating the transparent film with a laser. That is, when the transparent electrode film is patterned into a predetermined electrode shape, laser ablation is employed and irradiation conditions are appropriately selected. As a result, the surface of the transparent electrode film in the non-display area is actively roughened, and simultaneously with patterning the electrodes, a transparent film having irregularities in the non-display area or a minute island-shaped transparent film can be formed. it can.

  In the case where the concavo-convex or minute island-shaped transparent film is formed of a transparent conductive film, it is necessary to be non-contact with the transparent electrode so as not to be electrically connected to the transparent electrode in the display region. However, each island does not have to be completely independent, and may be a discontinuous film in which the islands are partially connected.

  In this embodiment, the character display includes a pattern display that displays the pattern shape to be displayed as it is, and a segment display that displays numbers by selecting a plurality of display elements. The dot matrix display is a system in which pixels are arranged in a lattice pattern, and necessary images are driven to display an image as a collection of pixels.

  Hereinafter, the structure of the liquid crystal display device of this embodiment will be specifically described. This liquid crystal display device uses a liquid crystal cell having the structure shown in FIGS. As shown in FIG. 1, the liquid crystal cell has a structure in which two glass substrates 10 are opposed to each other with a predetermined interval, a liquid crystal 13 is filled therebetween, and the periphery is sealed with a main sealing material 14. is there. On the opposing surfaces of the two glass substrates 10, an ITO film 11 and an alignment film 12, which are transparent electrode films, are laminated. Here, an ITO film is used as the transparent electrode film, but other transparent conductive films such as a tin oxide film and a zinc oxide film can also be used.

  As shown in FIG. 2, the liquid crystal cell has a character display area 213 and a dot matrix display area 214, and the periphery thereof is a non-display area 210. The ITO film 11 in the character display area 213 and the dot matrix display area 214 is patterned in the shape of predetermined electrodes 201, 203, and 204 as shown in FIG. In the non-display area 210, the ITO film 11 having an uneven surface or the island-like discontinuous ITO film 11 is disposed. The uneven or island-like ITO film 11 in the non-display area 210 is not in contact with the ITO film 11 in the electrodes 201, 203, and 204 in the display areas 213 and 214.

  The electrode shape will be described. The electrode 201 in the character display area 213 is composed of two digits each having seven segments. The ITO film 11 is patterned in the shape of each segment electrode 201. The ITO films 11 of the two opposing substrates 10 are patterned in the same shape. In the dot matrix display area 214, display is performed by the square pixels 202 arranged in a matrix. For this reason, the ITO film 11 of one substrate 10 is patterned into the shape of a plurality of line-like electrodes 203 arranged in parallel at a predetermined width and interval. The ITO film 11 of the other substrate 10 is patterned in the shape of a plurality of line electrodes 204 arranged in a direction orthogonal to the line electrodes 203. A portion where the line-shaped electrodes 203 and 204 that are orthogonal to each other overlap each other constitutes a pixel 202.

  As shown in FIG. 1, a conductive material 15 is provided outside the main seal material 14 to enable power supply from one glass substrate 10 side to the ITO film 11 of the other glass substrate 10. In addition, polarizing plates 16 are disposed on the outer sides of the two glass substrates 10, respectively. A liquid crystal display device is configured by combining the liquid crystal cell of FIGS. 1 and 2 with a backlight, a control circuit, and the like.

Next, a manufacturing method of the liquid crystal cell of FIG. 1 will be described with reference to FIG.
First, before entering the manufacturing process, conditions for laser irradiation are obtained by experiments. In this embodiment, the ITO film 11 is processed into the shape of the predetermined electrodes 201, 203, and 204 by laser ablation, and at the same time, the ITO film 11 around the electrode that has been completely removed conventionally has an uneven surface. Alternatively, it is processed into a fine island-like film and left. Therefore, in the region irradiated with the laser, the ITO film 11 is uneven or island-like, and the ITO film 11 in the region where the uneven or island-like ITO film 11 is not irradiated (electrodes 201, 203, 204) is electrically conductive. The laser irradiation condition that satisfies the condition of “No” is obtained by experiment. This experiment is performed using a sample in which the ITO film 11 is formed on the substrate 10.

  When the uneven ITO film 11 is left, the surface roughness (Ra) is desirably 50 nm or more.

  When the island-like ITO film 11 is left, it is desirable that the island diameter is 100 nm or more and 100 μm or less. By setting the island diameter to 100 nm or more, the alignment of a plurality of, for example, 20 or more liquid crystal molecules can be influenced by one island. However, the island diameter needs to be smaller than the distance between the electrodes. The thickness of the island-like ITO film 11 is desirably 20 nm or more. By setting the thickness to 20 nm or more, when the island diameter is 100 nm, the liquid crystal molecules at the interface with the island-like ITO film 11 can be inclined at an inclination angle of about 20 °. According to the experiments and experiences of the inventors, when the tilt angle of the liquid crystal molecules at the interface is 20 °, the local pretilt angle in the vicinity of the interface is about 5 °. When the local pretilt angle near the interface is about 1.5 to 5 °, the pretilt angle of the entire liquid crystal thickness can be about 1.5 to 1.8 °.

  Specifically, the experiment is performed as follows. A plurality of samples having an ITO film 11 formed on a glass substrate 10 are prepared, and various parameters such as wavelength, laser output, repetitive pulse period, and laser moving speed are changed to change the ITO film 11 into a predetermined electrode shape, for example, Laser ablation for processing the electrodes 201, 203, and 204 is performed. After that, for each sample, whether it is processed into the shape of the desired electrodes 201, 203, 204, whether the uneven or island-like ITO film remains in the region irradiated with the laser, and the electrodes 201, 203 , 204 and the concavo-convex or island-like ITO film 11 are evaluated. Thereby, the optimal laser irradiation conditions are selected. According to the experiments by the inventors, basically, the condition that the laser pulse frequency is low and the laser moving speed is high, and the distribution of the irradiation intensity of the laser beam depending on the location is suitable.

  After selecting the laser irradiation conditions, the respective steps shown in FIG. 2 are carried out for manufacturing. Each process will be described in turn. First, in the film forming step 301, the ITO film 11 is formed on the two glass substrates 10 by vapor deposition or the like.

  Next, in the laser ablation process 302, the ITO film 11 is patterned into the shapes of the electrodes 201, 203, and 204 in FIG. At this time, parameters such as a laser wavelength, a laser output, a repetitive pulse period, and a laser moving speed are set to conditions obtained in advance as described above. Thus, the ITO film 11 in the non-display area 210 around the electrodes 201, 203, and 204 is not completely removed, but the uneven or minute island-shaped ITO film 11 is left.

  Next, in step 304, the alignment film 12 is applied on the ITO film 11 by a flexographic printing machine, an ink jet coating apparatus, or the like. Thereafter, the alignment film 12 is rubbed. In the next step 305, a gap agent is sprayed on the two substrates 10 that have been subjected to the rubbing process, the main sealant 14 is attached by printing or the like, the two substrates 10 are stacked so that the alignment film 12 faces each other, and the gap is formed between them. Liquid crystal 13 is injected and sealed with an end seal material, and polarizing plates 16 are attached to both outer side surfaces. Further, the conductive material 15 is disposed outside the main seal material 14. This completes the liquid crystal cell. A backlight, an electric circuit, and the like are attached to the liquid crystal cell by a known method to complete a liquid crystal display device.

  In the completed liquid crystal display device, the display state (transmittance) of the non-selection electrodes in the display regions 213 and 214 and the non-display region 210 is substantially equal during multiplex driving. Thereby, the difference in display state between the non-display area and the non-selection electrode area is hardly recognized, and the display quality can be improved. This is because the pre-tilt angle of the liquid crystal 13 is slightly increased by leaving the ITO film 11 in an uneven or island shape in the non-display area 210, and the liquid crystal 13 in a state where the liquid crystal 13 has risen slightly when a non-selection voltage is applied. The main cause is considered to be almost equal to the display state. Further, there is a possibility that the liquid crystal alignment in the horizontal direction is slightly disturbed by the surface state of the uneven or island-like ITO film 11.

  Further, in the liquid crystal display device of this embodiment, the uneven or island-like ITO film 11 exists also in the non-display region outside the electrode, so that the charge is difficult to accumulate, and static electricity is applied to the liquid crystal display device. Are unlikely to malfunction.

  Furthermore, the laser ablation method of the present embodiment can pattern electrodes at a lower cost than the photolithography method. Moreover, in the conventional laser ablation method, it is necessary to select a condition that does not damage the underlying substrate 10 while completely removing the ITO film in the non-display area, so the processing conditions are very severe, and There is a problem that it takes time because the laser needs to be sufficiently irradiated (slow tact). However, in this embodiment, the ITO film 11 is left in an irregular shape or island shape, and therefore, the laser irradiation condition is the conventional one. It is relatively easy to find the optimum condition rather than severe. In addition, since the ITO film 11 does not have to be completely removed, there is an advantage that the tact time is fast.

  In the above embodiment, the uneven or island-like ITO film is left in the non-display area for both of the two substrates 10 facing each other, but only the one substrate 10 is left and the other substrate 10 is left. Can be configured to completely remove the ITO film 11 in the non-display area. Even in this case, since the alignment of the liquid crystal is slightly disturbed on the one substrate side, it is possible to obtain a predetermined effect that the non-selective electrode becomes difficult to see.

  The present invention relates to a liquid crystal display device for performing, for example, character display or mixed display of character display and full dot matrix display, in particular a vehicle-mounted display (car navigation, multi-information, cluster display, center console, etc.), aircraft The present invention can be applied to displays, display devices for games, mobile phone / DSC (digital still camera) display units, and audio device display units.

Example 1
As Example 1, a liquid crystal display device having the configuration shown in FIGS. 1 and 2 described in the embodiment was manufactured. The manufacturing procedure is as described in the embodiment. In the film forming step 301, the ITO film 11 having a thickness of 0.15 μm was formed. In the laser ablation process 302, the electrodes 201, 203, and 204 were patterned using a YVO (Nd: YVO ₄ ) laser. The laser irradiation conditions were set to a wavelength of 1064 nm, an output of 5 W, a repetitive pulse period of 10 kHz, and a laser moving speed of 500 mm / sec.

  FIG. 4 shows the result of measuring the cross-sectional shape of the sample processed under the above conditions by scanning the probe on the film surface. The flat portions at both ends in FIG. 4 are portions of the ITO film 11 (electrodes 201 and the like) that are not irradiated with laser, and the central region 40 is irradiated with laser to process the ITO film 11 into irregularities or minute island shapes. This is a portion (non-display area 210). As is apparent from FIG. 4, a fine uneven shape was observed in the central region 40, and the surface roughness (Ra) was about 800 nm. This is because in the central region 40, the ITO film 11 is not completely removed and remains in the form of minute islands. The remaining island-like ITO film 11 was not continuous in the lateral direction, and even if the ITO film 11 remained, there was no electrical conductivity in the lateral direction.

  Next, it progressed to the process 304, and after wash | cleaning the board | substrate 10 with the ITO film | membrane 11 patterned, the alignment film 12 was printed. Here, SE-410 (manufactured by Nissan Chemical Industries, Ltd.), which is a low pretilt alignment film material, was used. After the rubbing treatment, the gap agent was sprayed and the main seal material 14 was printed, and the substrates were stacked to produce an empty cell. Liquid crystal was vacuum injected into the empty cell, the inlet was sealed with an end sealant, and a polarizing plate was attached to prepare a liquid crystal cell.

  As the liquid crystal material, TN (Twisted Nematic) liquid crystal (manufactured by Merck) was used. The orientation direction between both substrates 19 was set to be 90 °. The liquid crystal cell thickness was 5 microns here. The liquid crystal material has a positive dielectric anisotropy Δε and a refractive index anisotropy Δn of about 0.15. Note that a liquid crystal having a negative Δε may be used.

(Comparative Example 1)
As Comparative Example 1, a laser cell was manufactured by changing the laser irradiation conditions in the laser ablation process 302 of Example 1 to conventional irradiation conditions and making the other conditions the same as in Example 1. The laser irradiation conditions were a wavelength of 1064 nm, an output of 20 W, a repetition pulse period of 20 kHz, and a laser moving speed of 300 mm / sec.

  FIG. 5 shows the result of measuring the cross-sectional shape of the sample processed under the above conditions by scanning the probe on the film surface. The flat portions at both ends in FIG. 5 are the portions of the ITO film 11 (electrodes 201 etc.) that are not irradiated with the laser, and the central region 50 is the portion (non-display region) where the ITO film 11 is removed by irradiating the laser. is there. Although the region 50 is slightly uneven, it can be seen that the unevenness is small compared to the uneven shape of the central region 40 in FIG. 4 and the ITO film 11 is almost completely removed. If it is the conventional evaluation method of the patterned ITO film 11, it will be obvious from the common knowledge of those skilled in the art that the comparative example in which the ITO film 11 in the non-display area is completely removed is preferable.

(Evaluation)
The liquid crystal cells fabricated in Example 1 and Comparative Example 1 were each multiplex driven, and a non-selection voltage (1/4 Duty, 1/3 Bias, 5 V) was applied to each electrode 201, 203, 204. The liquid crystal cell of Example 1 and the liquid crystal cell of Comparative Example 1 were observed from the front and oblique directions (about 30 °), and photographs were taken. FIG. 6a shows a photograph of the front surface of the liquid crystal cell of Example 1, and FIG. 6b shows a photograph from an oblique direction. FIG. 7a shows a photograph of the front surface of the liquid crystal cell of Comparative Example 1, and FIG. 7b shows a photograph from an oblique direction. As shown in FIGS. 7a and 7b, it can be seen that the liquid crystal cell of Comparative Example 1 is in an unfavorable display state because the pattern of the segment electrode 201 is visible even though the liquid crystal cell is off-display. On the other hand, in the liquid crystal cell of Example 1 of FIGS. 6a and 6b, the display state of the non-selection electrode 201 and the non-display area 210 is substantially equal, and therefore the segment electrode 201 can be observed from either the front or the oblique direction. The pattern was hardly recognized and it was confirmed that it was a very preferable display state.

  When the pretilt angles of the liquid crystal cells of Example 1 and Comparative Example 1 were measured by the crystal rotation method, the pretilt angle of the non-display area 210 of Example 1 was 1.8 °. On the other hand, the pretilt angles when the non-selection voltage was applied to the display areas 213 and 214 of the example and the display area of the comparative example were all 1.5 °. (The pretilt angle of the non-display area (area without electrode) of the comparative example was 1.5 °.) From this, the liquid crystal cell of Example 1 has an uneven or island-like ITO film in the non-display area 210. It was confirmed that by leaving 11 the pretilt angle was slightly increased, a non-selection voltage was applied, and it was almost equal to the slightly raised state.

  In the non-display area 210 of Example 1, the pretilt angles were measured at a plurality of measurement points, but the obtained pretilt angles were almost the same. This is because each concavo-convex shape of the concavo-convex or island-like ITO film 11 (the concavo-convex shape of the region 40 in FIG. 4) does not directly affect the pretilt angle, but the effect of the concavo-convex is macroscopic. This is considered to be because the average pretilt angle is obtained. For this reason, there was no distribution in the liquid crystal display state at the level seen visually, and display unevenness and the like were not observed. In addition, when the pretilt angle of a micro area | region is measured using a microscope etc., the uneven | corrugated shape may have influenced the pretilt angle.

  In Example 1, a low pretilt alignment film material was used, but a high pretilt alignment film material can also be used. A vertical alignment film can also be used. In the first embodiment, TN has been described as the liquid crystal display mode, but the STN mode may be used.

(Example 2)
As Example 2, a VA mode liquid crystal cell was manufactured. The structure of the liquid crystal cell of Example 2 is the same as in FIG. 1, but a vertical alignment film was used as the alignment film 12. First, a substrate 10 with an ITO film 11 (with a film thickness of 0.15 microns) was prepared, and the ITO film 11 was patterned into a predetermined electrode shape using a YVO laser. As in the case of FIG. 2, the electrode shape is a pattern in which dot matrix display and character display are mixedly displayed. The laser irradiation conditions were the same as in Example 1. That is, the laser wavelength was 1064 nm, the output was 5 W, the laser pulse frequency was 10 kHz, and the laser moving speed was 500 mm / sec. The cross-sectional shape of the ITO film 11 after patterning is the same as in FIG. 4, and the ITO film 11 processed into irregularities or minute islands remains in the region irradiated with the laser around the electrode.

  The patterned substrate 10 was washed, and a vertical alignment film was formed as the alignment film 12 by printing. Here, the vertical alignment film 12 was formed using SE-1211 (manufactured by Nissan Chemical Industries, Ltd.). In addition, as a method for obtaining uniform monodomain alignment, a known method can be used, and for example, a method described in JP-A-2005-234254 can be used.

  Next, a rubbing process was performed. The rubbing process is a process in which a cylindrical roll wound with a cloth is rotated at high speed and rubbed on the alignment film, whereby liquid crystal molecules can be aligned uniaxially. In Example 2, the rubbing process was performed so that the alignment state between the upper and lower substrates 10 was in an antiparallel (antiparallel) state. A gap agent was sprayed between the two substrates 10 to print the main seal pattern. As the sealant, thermosetting sealant ES-7500 (manufactured by Mitsui Chemicals, Inc.) was used. This sealant contains several percent of glass fibers having a size of 3.9 μm. As the sealant, it is also possible to use a photocurable sealant or a combined light / heat type sealant.

  In addition, a conductive material including an Au ball (a gold agent coated around the gap agent) was disposed at a predetermined position by printing. In this example, screen printing was performed using a sealing material (ES-7500) with a few percent of 4.5 μm Au balls added as a conductive material. The sealant pattern (and the conductive material pattern) was formed only on the substrate 10 on one side, and the gap control agent was sprayed on the opposite substrate 10 by a dry spraying method. In this embodiment, a plastic ball of 4 μm is used as the gap agent, but silica fine particles (for example, trade name: Shinsyukyu, manufactured by Catalytic Chemical Industry Co., Ltd.) may be used. It is also possible to use a gap agent that has been surface-treated so as not to disturb the alignment of the liquid crystal 13.

  The upper and lower substrates 10 were overlapped at predetermined positions to form cells, and the sealing agent was cured by heat treatment in a pressed state. Next, the glass was scratched with a scriber device, and divided into predetermined sizes and shapes by breaking. Liquid crystal 13 was injected into this cell by vacuum injection, and the injection port was sealed with an end sealant. As the liquid crystal 13, a liquid crystal having a negative dielectric anisotropy Δε (refractive index anisotropy Δn: 0.09) (manufactured by Merck & Co., Inc.) was used.

  The polarizing plate 16 was pasted in a predetermined pattern (crossed Nicol, 45 ° with respect to rubbing). Thus, a vertically aligned liquid crystal cell (normally black) was prepared. It is also possible to use a polarizing plate 16 with a visual (optical) compensation plate.

(Comparative Example 2)
As Comparative Example 2, the conditions of laser irradiation in Example 2 were changed, and the ITO film 11 was patterned. Here, a YAG laser was used. The laser irradiation conditions are the same as in Comparative Example 1. That is, the laser wavelength was 1064 nm, the output was 20 W, the laser pulse frequency was 20 kHz, and the laser moving speed was 300 mm / sec. The cross-sectional shape of the patterned ITO film 11 was the same as in FIG. 5, and the ITO film 11 was almost completely removed from the periphery of the electrode.

  A liquid crystal cell was produced in the same manner as in Example 2 using the substrate 10 of the ITO film 11. Except for the patterning conditions of the ITO film 11, it was the same as in Example 2.

(Evaluation)
A drive circuit or the like was connected to the liquid crystal cells of Example 2 and Comparative Example 2 to produce a liquid crystal display device, and dot and character mixed display by multiplex drive was performed. The dot display portion was driven and displayed at 1/16 duty, and the character display portion was driven at 1/4 duty. In the liquid crystal display device using the liquid crystal cell of Comparative Example 2, since the off display portion (non-selection voltage application portion) of dot display has light leakage compared to the non-display region where the ITO film 11 is not disposed, It looked up. On the other hand, in the liquid crystal display device using the liquid crystal cell of Example 2, the display state of the off-display portion (non-selection voltage application portion) and the display state of the non-display region are almost the same, and a clean display without any sense of incongruity Can be obtained in a VA mode liquid crystal display device.

Explanatory drawing which shows the cross-section of the liquid crystal cell of this Embodiment. The top view which shows the shape of the electrode (ITO film | membrane 11) of the liquid crystal cell of this Embodiment. Explanatory drawing which shows the manufacturing process of the liquid crystal cell of this Embodiment. 3 is a graph showing a cross-sectional structure of an island-shaped ITO film processed by laser irradiation in the liquid crystal cell of Example 1. The graph which shows the cross-section of the ITO film | membrane processed in the liquid crystal cell of the comparative example 1 by laser irradiation. The photograph which applied the non-selection voltage to the electrode of the liquid crystal cell of Example 1, and image | photographed the display state from the front. The photograph which applied the non-selection voltage to the electrode of the liquid crystal cell of Example 1, and image | photographed the display state from the diagonal direction. The photograph which applied the non-selection voltage to the electrode of the liquid crystal cell of the comparative example 1, and image | photographed the display state from the front. The photograph which applied the non-selection voltage to the electrode of the liquid crystal cell of the comparative example 1, and image | photographed the display state from the diagonal direction.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Glass substrate, 11 ... ITO film, 12 ... Orientation film, 13 ... Liquid crystal, 14 ... Main seal material, 15 ... Conductive material, 16 ... Polarizing plate, 201 ... Segment electrode, 202 ... Pixel, 203, 204 ... Line shape Electrodes, 210 ... non-display area, 213 ... character display area, 214 ... dot matrix display area.

Claims (8)

A pair of transparent substrates disposed opposite to each other, transparent electrodes having predetermined shapes respectively disposed on opposite surfaces of the pair of transparent substrates, and a liquid crystal sandwiched between the substrates,
A liquid crystal display device, wherein at least one of the pair of transparent substrates is provided with a transparent film having irregularities on the surface in a region where the transparent electrode is not disposed.   2. The liquid crystal display device according to claim 1, wherein the transparent film having irregularities on the surface is an island-like discontinuous film.   3. The liquid crystal display device according to claim 1, wherein the transparent film and the transparent electrode are both formed of a transparent conductive film and are not in contact with each other. The liquid crystal display device according to any one of claims 1 to 3, further comprising a circuit that drives the liquid crystal by applying a voltage to the transparent electrode,
A plurality of the transparent electrodes are respectively disposed on the pair of transparent substrates, and the circuit selectively applies one of a predetermined selection voltage and a non-selection voltage to the transparent electrodes by multiplex driving. Liquid crystal display device. A method of manufacturing a liquid crystal display device including a substrate provided with a transparent electrode of a predetermined shape,
By irradiating the substrate provided with the transparent conductive film with laser light, the transparent conductive film is processed into the transparent electrode having the predetermined shape, and at the same time, the surface of the transparent conductive film in the peripheral region of the transparent electrode is made uneven. A manufacturing method of a liquid crystal display device characterized by processing.   6. The method for manufacturing a liquid crystal display device according to claim 5, wherein the transparent electrode is in non-contact with the transparent conductive film in a peripheral region thereof.   7. The method for manufacturing a liquid crystal display device according to claim 5, wherein the transparent conductive film in the peripheral region of the transparent electrode is processed into an island-like discontinuous film by irradiation with the laser beam. Manufacturing method of liquid crystal display device   8. The method of manufacturing a liquid crystal display device according to claim 5, wherein the laser beam is a YVO laser beam or a YAG laser beam.

Images