JP5325069B2 - Liquid crystal display element and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display element capable of displaying excellently. <P>SOLUTION: The liquid crystal display element includes: a first transparent substrate including a first polarizing film having a plurality of spiral patterns or radial patterns, and a first transparent electrode; a second transparent substrate arranged opposite to the first transparent substrate, and including a second polarizing film having a plurality of spiral patterns or radial patterns, and a second transparent electrode; and a liquid crystal layer sandwiched between the first transparent substrate and the second transparent substrate. When viewed from a normal direction of the first and second transparent substrates, a pixel is demarcated on a position where the first transparent substrate is faced with the second transparent substrate, and the center of the spiral patterns or the radial patterns of the first polarizing film agrees with the center of the spiral patterns or the radial patterns of the second polarizing film, wherein both centers are arranged out of the pixel. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a liquid crystal display (LCD) and a method for manufacturing the same.

  In a general liquid crystal display element, a stretched film type polarizing plate is disposed outside the liquid crystal cell. The polarizing plate is produced by forming a resin in which iodine or a dye is dispersed into a film and stretching it in a uniaxial direction.

  FIG. 9 shows an isocontrast curve of a twisted nematic (TN) type liquid crystal display device in which a stretched film type polarizing plate is arranged outside the liquid crystal cell. The azimuth in the substrate surface of the liquid crystal display element is represented by azimuth angles of 0 °, 90 °, 180 ° and 270 ° along the circumferential direction of the circle. The 270 ° -90 ° azimuth represents the left-right azimuth of the liquid crystal display element, and the 180 ° -0 ° azimuth represents the vertical azimuth of the liquid crystal display element. An angle of 0 ° to 50 ° along the radial direction of the circle represents an inclination angle from the normal direction of the substrate. The 0 ° position (the center of the circle) indicates the contrast of the liquid crystal display element observed from the substrate normal direction. The observation position where the contrast is 10 is displayed by a curve connecting black circles. In addition, the observation positions where the contrast is 20 and 50 are displayed by a curve connecting white circles and a curve connecting black squares.

  It can be clearly seen that the contrast has a large viewing angle dependency. As can be seen from FIG. 9, in the liquid crystal display element having a configuration in which a stretched film type polarizing plate is arranged outside the liquid crystal cell, it is difficult to realize good viewing angle characteristics.

  A stretched film type polarizing plate has low durability against heat, humidity, light, and the like. For this reason, in a liquid crystal display element in which a stretched film type polarizing plate is disposed outside the liquid crystal cell, the reliability of the liquid crystal display element is lowered due to deterioration of the polarizing plate even if the quality of the liquid crystal cell is maintained. There is a problem.

  Furthermore, in a stretched film type polarizing plate produced by stretching in a uniaxial direction, the polarization axis (transmission axis or absorption axis) can be controlled only in one direction, and thus the viewing angle dependency occurs due to the polarizing plate itself. .

  With reference to FIG. 10 (A)-(C), the viewing angle dependence resulting from polarizing plate itself is demonstrated.

  As shown in FIG. 10A, two polarizing plates produced by stretching in a uniaxial direction are arranged in crossed Nicols. When this is observed from the normal direction of the polarizing plate, the angle formed by the polarization axes of the two polarizing plates is 90 °.

  Reference is made to FIG. When the polarizing plate arranged in crossed Nicols is observed from the direction inclined from the normal direction of the polarizing plate to the direction of the polarizing axis, the angle formed by the polarizing axes of the two polarizing plates is 90 °.

  Reference is made to FIG. When the polarizing plate arranged in crossed Nicols is observed from a direction inclined from the normal direction of the polarizing plate to an orientation different from the orientation of the polarization axis (for example, an orientation shifted by 45 ° from the orientation of the polarization axis), The angle formed by the polarization axes of the two polarizing plates is greater than 90 °. Thus, when observing from the direction in which the polarization axes of the two polarizing plates form an angle different from 90 °, light leakage often occurs, and the display quality of the liquid crystal display element deteriorates.

  In order to compensate for light leakage due to the polarizing plate, a method using a combination of a positive A plate and a positive C plate or a method using a biaxial retardation film has been proposed. Since it is expensive, the cost of the liquid crystal display element is increased. Moreover, since it also increases the thickness of the liquid crystal display element, it is not suitable for use in products that require thinness, such as mobile LCDs and mobile phones.

  An invention of an axially symmetric polarizing plate that has high contrast and can be manufactured thermally and stably is disclosed (for example, see Patent Document 1). In Patent Document 1, the axially symmetric shape is a point-symmetric plane shape, and when the shape is rotated around the center point, it can be superposed on the original shape at or around the required rotation angle. Refers to the shape.

  An invention of a multi-axis polarizer characterized by holding a dichroic substance and causing the direction of the polarization axis to be different is also known (see, for example, Patent Document 2). In Patent Document 2, (a) a multi-axis showing a radial polarization axis obtained by spin-coating a black polarizing ink comprising a lyotropic liquid crystal containing a dichroic dye on a saponification-treated surface of a triacetyl cellulose film Polarizer, (b) A polypolar film having concentric circular polarization axes obtained by coating black polarizing ink on a saponification-treated surface of a triacetyl cellulose film while applying a shearing force with a rotating disk-shaped substrate. An axial polarizer is described as an example.

  Various techniques for controlling the alignment direction of the liquid crystal are known (see, for example, Patent Document 3). In Patent Document 3, a photomask having a slit-like light transmission portion and a light source are arranged outside the alignment film whose surface properties change due to light irradiation, and the relative positional relationship between the photomask and the light source is constant. In this state, while rotating the alignment film relative to the photomask, the alignment film is irradiated with light at a certain oblique incident angle via the light transmission part, and thereby the alignment film is photo-aligned. A photo-alignment method for applying is described. By the photo-alignment method described in Patent Document 3, concentric or radial liquid crystal alignment can be obtained. Since the liquid crystal alignment can be continuously changed, defects such as disclination lines do not occur, multi-domain alignment is obtained, and a liquid crystal display element with a wide viewing angle can be realized.

  FIG. 11 shows an isocontrast curve of a liquid crystal display element in which a stretched film type uniaxial polarizing plate is arranged in a crossed Nicol state in a liquid crystal cell that has been subjected to alignment treatment by the method described in Patent Document 3. The meanings of azimuth angles of 0 °, 90 °, 180 °, 270 ° along the circumferential direction of the circle, and inclination angles of 0 ° to 50 ° along the radial direction of the circle are the same as those in FIG. The display method of the isocontrast curve with the contrast of 10, 20, 50 is the same as in FIG. The polarization axis of the uniaxial polarizing plate is arranged in a 270 ° -90 ° azimuth and a 180 ° -0 ° azimuth.

  Although it shows a relatively wide field of view characteristics, it is different from the polarization axis orientation (especially 45 °, 135 °, 225 °, etc.) compared to the polarization axis orientation (270 ° -90 ° orientation, 180 ° -0 ° orientation). It can be seen that the contrast in the 315 ° azimuth is low. This is considered to be due to viewing angle dependency (light omission depending on the observation direction) caused by the polarizing plate itself. Thus, when the liquid crystal display element is manufactured by combining the invention described in Patent Document 3 with a uniaxial polarizing plate, the advantages of the invention may not be fully utilized.

  Further, it can be seen that the liquid crystal display element having an isocontrast curve in FIG. 11 has a slightly lower average contrast value than the liquid crystal display element having the contrast characteristics of FIG. In the liquid crystal display element to which the technology described in Patent Document 3 is applied, the liquid crystal molecules are aligned concentrically or radially, so that the liquid crystal molecules arranged in an orientation different from the polarization axis orientation of the polarizing plate arranged in crossed Nicols are arranged. It must exist. Such a liquid crystal molecule has a larger wavelength dispersion of light transmittance than a liquid crystal molecule aligned in an orientation parallel or orthogonal to the polarization axis orientation. For this reason, the contrast is lowered.

  In order to produce a circular polarizing plate, it is desirable to use nanoimprint technology from the viewpoint of mass productivity. Nanoprint technology is a kind of precise mold technology that reversely transfers a mold called a mold. Specifically, by heating the temperature of a silicon substrate having a metal layer and a resist layer laminated on the surface to about 200 ° C., the resist layer is softened, and a mold having a circular pattern separately formed on the softened resist layer Is pressed and held (13 Mpa) and cooled to cure the resist layer, the mold is peeled off from the resist layer, and the remaining film in the recesses of the resist layer generated by the mold pressing is removed by oxygen RIE or the like. Thereafter, the metal layer is etched and the resist layer is removed, thereby producing a polarizing plate having a circular pattern.

Japanese Patent Laid-Open No. 9-21913 Japanese Patent Laid-Open No. 2001-215489 JP 2002-82333 A

  In the case of a mold having a circular pattern, when the mold is pressed against a resist layer formed on a silicon substrate, a softened resist flow cannot be made and fine bubbles may remain. . Even if the remaining bubbles are very fine, the function as a polarizing plate is lost in the portion, and the performance as a liquid crystal display device is greatly deteriorated.

  Further, in the step of holding pressure, the pressure condition is set assuming that there are essentially no bubbles (all as a liquid resist material). However, if bubbles enter, they are substantially added to the resist. If the pressure is low or there are variations in the location where bubbles are generated, the pressurized state may become uneven depending on the location. In such a state, the thickness of the remaining film of the concave portion of the resist layer varies depending on the location, and the distance between the metal portions varies depending on the location, or in a severe case, the metal layer is not completely etched, and depending on the location Or, in the worst case, the function of the polarizing plate cannot be exhibited on the entire surface.

  An object of the present invention is to provide a liquid crystal display element capable of realizing good display.

  Moreover, it is providing the manufacturing method which can manufacture the liquid crystal display element which can implement | achieve favorable display.

According to an aspect of the present invention, a liquid crystal display element includes a first transparent substrate including a first polarizing film having a plurality of spiral patterns or radial patterns, and a first transparent electrode, and the first transparent substrate. A second transparent substrate including a second polarizing film disposed opposite to the substrate and having a plurality of spiral patterns or radial patterns; and a second transparent electrode; the first transparent substrate; and the second transparent substrate. And a position where the first transparent electrode and the second transparent electrode face each other when viewed from the normal direction of the first and second transparent substrates. And the center of the spiral pattern or radial pattern of the first polarizing film coincides with the center of the spiral pattern or radial pattern of the second polarizing film, and is disposed outside the pixel. Has been.

According to another aspect of the present invention, a method for manufacturing a liquid crystal display element includes: (a) a first transparent substrate on which a first transparent electrode is formed, and a second transparent substrate on which a second transparent electrode is formed. And a liquid crystal layer sandwiched between the first and second transparent substrates, and when viewed from the normal direction of the first and second transparent substrates, the first transparent electrode and the second transparent substrate Preparing a liquid crystal cell in which pixels are defined at a position facing the transparent electrode; and (b) disposing a first polarizing film having a plurality of spiral patterns or radial patterns on the first transparent substrate. And disposing a second polarizing film having a plurality of spiral patterns or radial patterns on the second transparent substrate, and in the step (b), the first transparent substrate and the second transparent substrate When viewed from the normal direction, the spiral pattern or radial pattern of the first polarizing film Turn the center of, is matched with the center of the spiral pattern or a radial pattern of the second polarizing film, and is arranged outside the pixel.

  ADVANTAGE OF THE INVENTION According to this invention, the liquid crystal display element which can implement | achieve favorable display can be provided.

  In addition, it is possible to provide a manufacturing method capable of manufacturing a liquid crystal display element capable of realizing good display.

(A)-(G) are schematic sectional drawings which show the preparation methods of the board | substrate with a polarizing film of the liquid crystal display element by a 1st Example. (A) And (B) is a schematic plan view which shows the pattern of the mask 70a. (A) And (B) is a schematic plan view which shows the pattern of the mask 70b. (A)-(G) are schematic sectional drawings which show the preparation process of the mold 90. FIG. (A)-(E) is a figure for demonstrating the manufacturing method of the liquid crystal display element by a 1st Example. 2 shows an isocontrast curve of the liquid crystal display element according to the first embodiment. (A)-(E) is a figure for demonstrating the manufacturing method of the liquid crystal display element by a 2nd Example. The isocontrast curve of the liquid crystal display element by a 2nd Example is shown. 2 shows an isocontrast curve of a twisted nematic type liquid crystal display element in which a stretched film type polarizing plate is disposed outside a liquid crystal cell. (A)-(C) are the figures for demonstrating the viewing angle dependence resulting from polarizing plate itself. An isocontrast curve of a liquid crystal display element in which a stretched film type uniaxial polarizing plate is arranged in crossed Nicols is shown in a liquid crystal cell that has been subjected to an alignment treatment by the method described in Patent Document 3.

  1A to 1G are schematic cross-sectional views illustrating a method for manufacturing a substrate with a polarizing film of a liquid crystal display device according to a first embodiment.

  Reference is made to FIG. For example, a 1000 mm thick molybdenum (Mo) film (metal film 52) is formed by sputtering on a cleaned glass substrate 51 having a thickness of 0.7 mm. The thickness of the metal film 52 may be 300 mm or more, but if it is thin, light leakage occurs, and if it is thick, the patterning property is lowered. Note that the conductive film on the glass substrate 51 is not limited to Mo, and may be formed of a metal such as aluminum, chromium, or titanium.

  A resist material made of UV curable resin is coated on the metal film 52 to a thickness of 1 μm by spin coating to form a resist film 53. Not only spin coating but also slit coating, roll coating, combined use of spin coating and slit coating, and the like may be performed. The thickness of the resist film 53 is suitably 0.8 to 1.5 μm.

  Subsequently, a mask pattern (resist film) 53 is formed on the metal film 52. The mask pattern (resist film) 53 is formed by reverse transfer using a nanoimprint technique using a mold 90 having a spiral pattern 70a as shown in FIG. In this embodiment, an optical nanoimprint technique is used, but a thermal cycle nanoimprint technique may be used.

  FIG. 2A is a schematic plan view showing a pattern of a mask 70a formed on the glass substrate 51 using the nanoimprint technique. A spiral pattern is formed on the mask 70a at regular intervals in the vertical and horizontal directions. The line width of the line (metal line part, light shielding part) and the line width of the slit (opening part) along the radial direction of the spiral pattern are both about 0.1 μm. The spiral pattern is formed with a pattern pitch of 0.2 μm in the radial direction.

  By using a spiral pattern, the resist can make a flow, so the possibility of bubbles remaining between the resist on the substrate can be significantly reduced.

  The pattern obtained by nanoimprinting was about 1.5 μm at the thick part and about 0.1 μm at the thin part (residual film 53a in FIG. 1C).

  The spiral pattern corresponds to the pixel pattern (dot matrix) in the LCD substrate as shown in FIG. In the figure, a square pattern indicated by a dotted line is one pixel. It can be seen that one spiral pattern corresponds to four pixels.

Returning to FIG. 1B, the mold 90 is pressed against the resist film 53 in the air. When pressing the mold 90, it is ideal that the entire apparatus is evacuated so that bubbles do not enter between the mold 90 and the resist film 53 on the glass substrate 51. However, the apparatus is very expensive. Therefore, in this embodiment, the mold 90 is pressed in the atmosphere without vacuuming. While the mold 90 is held under pressure (for example, 13 MPa), ultraviolet exposure is performed from the glass substrate 51 side. The exposure is performed at a fluence of, for example, 80 mJ / cm ² in accordance with the sensitivity of the resist.

  Reference is made to FIG. After the exposure, the mold 90 is peeled off, pre-baked and developed. An inorganic alkaline aqueous solution of KOH was used as the developer. Commercially available developers can also be used. As a commercially available developer, for example, tetramethylammonium hydroxide (TMAH) generally used for developing a positive resist for lithography can be used. On the metal film 52, the resist film 53 remains in a pattern equal to the mask pattern of the mask 70a.

  At this time, the remaining film 53a remains in a portion corresponding to the convex portion 94 of the mold 90 between the mask pattern lines of the mask 70a. The remaining film is removed by etching using RIE or the like to obtain a state as shown in FIG.

Reference is made to FIG. The metal film 52 is etched by, for example, dry etching. In this embodiment, a mixed gas of SF ₆ and N ₂ is used.

When the metal film 52 is formed of molybdenum or titanium, CF ₄ , C ₂ F ₄ , C ₂ F ₆ , C ₃ F ₆ , C ₃ F ₈ , C ₄ F ₈ , C ₄ F ₁₀ , C ₅ F ₈ , C ₆ F ₁₄ , CF ₃ CFOCF ₂ , C ₆ F ₅ CF ₂ CFCF ₂ , CF ₃ Br, CF ₃ I, C ₂ F ₅ I, SF ₆ , NF ₃ , WF ₆ , C ₂ F ₅ Cl, _{C 2 F 4 C l2, CF} 3 Cl, CF 2 Cl 2, CFCl 3, CHF 3, CH 2 F 2, CHF 2 CF 3, CH 2 FCF 3, CH 3 CHF 2, C 2 H 3 F 3, C _{3 HF 7, CF 3 CH 2} CF 3, C 6 F 5 CHCH 2 or the like can be used. Also, when the metal film 52 is formed by _{chromium, Cl 2, CCl 4, SiCl} 4, BCl 3, PCl 3, CBrF 3, BBr 3, C 2 ClF 5, C 2 Cl 2 F 4, CClF 3, CCl ₂ F ₂ , CCl ₃ F, HCl, CH ₂ Cl ₂ , CHCl ₃ , HBr, or the like can be used.

  Note that a mixed solution of phosphoric acid, nitric acid, acetic acid, and water may be performed by wet etching using an etchant. Wet etching is performed at room temperature and is completed in about 10 seconds.

Reference is made to FIG. The resist film 53 is removed using an aqueous NaOH solution. Organic remover and ashing may be used. When dry etching is performed, ashing using O ₂ plasma or the like is desirable. Thus, in the present embodiment, the polarizing film-coated substrate 50 including the metal film (polarizing film 54) having the pattern of the mask 70a on the glass substrate 51 is manufactured.

  Reference is made to FIG. Similar to the procedure described with reference to FIGS. 1 (A) to 1 (F), similar to the pattern of the mask 70b on the glass substrate 61 (in this embodiment, the similarity ratio is 1: 1.25). A substrate 60 with a polarizing film including a Mo film (polarizing film 64) having a radial pattern of is prepared.

  FIG. 3A is a schematic plan view showing a pattern of a mask 70b formed on the glass substrate 61 by the nanoimprint technique when another substrate 60 with a polarizing film is manufactured.

  A radial pattern is formed on the mask 70b at regular intervals in the vertical and horizontal directions. The formation interval along the vertical and horizontal directions of the radial pattern is equal to that of the spiral pattern in the mask 70a shown in FIG. In each radial pattern, all lines and slits point to one point (the center of the radial pattern). However, since it is impossible to face one central point while maintaining both widths, the slit is oriented toward the center, and the slit width is always approximately 0.08 μm to 0.1 μm. To. As a result of actual creation by the inventors, a slit pattern of 0.1 μm was obtained in the finish when designed to be 0.08 μm on the mask. The width of the line is as much as possible with the direction as the center, and the width is close to 0.1 μm. In particular, the line width varies depending on the location, and is about 0.2 μm at the maximum. The distance between the centers of adjacent lines increases as the distance from the center of the radial pattern increases. At this time, the slit width is kept substantially constant. When the distance between adjacent lines becomes 0.3 μm along the vertical direction or the horizontal direction, each line and slit are continuous with those of the adjacent radial pattern.

  The radial pattern corresponds to the pixel pattern (dot matrix) in the LCD substrate as shown in FIG. In the figure, a square pattern indicated by a dotted line is one pixel. It can be seen that one radial pattern corresponds to four pixels.

  The inventors of the present application measured the light transmittance of the produced polarizing film-coated substrates 50 and 60 from the normal direction of the substrate. When the amount of light transmitted through the glass substrate having the same thickness (0.7 mmt) as the polarizing film-coated substrates 50 and 60 is 100%, the light transmittance of the polarizing film-coated substrate 50 including the Mo-polarized film 54 having a spiral pattern is 44. %Met. This value is higher than the light transmittance of a general polarizing film (about 42% as measured by the same measurement method). On the other hand, the light transmittance of the polarizing film-coated substrate 60 including the Mo polarizing film 64 having a radial pattern was 40%, which was smaller than the light transmittance of the polarizing film-coated substrate 50. It is considered that this is because the area of the Mo polarizing film 64 (line portion, light shielding portion) of the polarizing film-coated substrate 60 is larger than that of the polarizing film-coated substrate 50.

  Further, when the polarizing film-coated substrates 50 and 60 were overlapped so that the center of the spiral pattern coincided with the center of the radial pattern, the light transmittance was about 0.02%. This value is equivalent to the light transmittance when a general wire grid type polarizing plate is arranged in crossed Nicols.

  Furthermore, the light-shielding properties when the polarizing film-coated substrates 50 and 60 were observed from various orientations and polar angles were almost constant regardless of the observation orientation and polar angles. For example, it can be seen that light leakage depending on the observation azimuth and polar angle direction, which occurs when a polarizing plate having a polarization direction in a uniaxial direction is arranged in crossed Nicols, is prevented.

  FIG. 4 is a schematic cross-sectional view showing a manufacturing process of a mold 90 used in the mold pressing process shown in FIG. The mold 90 is manufactured using a general electron beam mask drawing apparatus.

Reference is made to FIG. A positive resist material is applied to a silicon substrate 91 having a thermally oxidized SiO ₂ film 92 formed on the surface to form a resist film 93.

Reference is made to FIG. Electron beam exposure is performed on the resist film 93 in a spiral pattern shown in FIG. Thereafter, as shown in FIG. 4C, development is performed, and the resist film 93 remains on the thermally oxidized SiO ₂ film 92 in a pattern equal to the spiral pattern shown in FIG.

Reference is made to FIG. A chromium coating 95 is formed on the patterned resist film 93 and the exposed thermally oxidized SiO ₂ film 92 to form a chromium film 95. Thereafter, the resist film 93 is removed by dissolving with, for example, acetone. As a result, as shown in FIG. 4E, the chromium film 95 remains on the thermally oxidized SiO ₂ film 92 in a pattern obtained by inverting the spiral pattern shown in FIG.

Reference is made to FIG. Dry etching is performed using the chromium film 95 having the reverse pattern as a mask, and the thermally oxidized SiO ₂ film 92 exposed between the patterns of the chromium film 95 is removed. Thereafter, chromium etching is performed to remove the chromium film 95, thereby completing the mold 90 having a pattern obtained by inverting the spiral pattern shown in FIG. 3A as shown in FIG.

  In addition, the mold for producing the radial pattern of the polarizing film-coated substrate 60 is also produced by the same process as shown in FIG. The pattern used at this time is as shown in FIG.

  Subsequent to the steps of manufacturing the polarizing film-coated substrates 50 and 60 shown in FIG. 1, a segment substrate on which segment electrodes are formed and a common substrate on which common electrodes are formed are manufactured.

  FIG. 5 is a schematic cross-sectional view for explaining a process for producing a segment substrate on which segment electrodes are formed and a common substrate on which common electrodes are formed.

  Reference is made to FIG. An ITO film 32 is formed by vapor deposition or sputtering on a transparent substrate, for example, a glass substrate 31 having a thickness of 0.7 mm.

  Reference is made to FIG. By patterning the ITO film 32 into a desired pattern, for example, a dot matrix pattern, by a photolithography process, a transparent electrode (segment electrode) 33 is formed, and the segment substrate 30 is obtained. An alignment film is formed on the transparent electrode 33.

  Reference is made to FIG. By patterning an ITO film formed on a transparent substrate, for example, a glass substrate 21 having a thickness of 0.7 mm, a transparent electrode (common electrode) 23 is produced, and the common substrate 20 is obtained. The alignment process of the common substrate 20 is not performed.

  A TFT (Thin Film Transistor) matrix may be formed on the segment substrate 30. A color filter (CF) pattern can be formed on the common substrate 20.

  In addition, you may produce the same pattern as the ITO pattern of the segment board | substrate 30 in the surface different from the polarizing film 54,64 formation surface of the board | substrates 50 and 60 with a polarizing film. In that case, it is desirable to protect the surfaces of the polarizing films 54 and 64 by attaching a protective film, forming a coating film, or the like. In addition, a pattern similar to the CF pattern of the common substrate 20 can be formed on a surface different from the surface on which the polarizing films 54 and 64 of the polarizing film-coated substrates 50 and 60 are formed.

  Reference is made to FIG. A liquid crystal layer 40 sandwiched between the segment substrate 30 and the common substrate 20 arranged to face each other in parallel is formed to manufacture a liquid crystal cell. A main seal pattern is printed on one substrate, for example, the segment substrate 30, and a gap control agent is spread and superimposed on the other substrate, for example, the common substrate 20, and liquid crystal containing a chiral agent is injected using a vacuum injection method. Liquid crystal dropping injection (One Drop Filling; ODF) may be used. A known technique, for example, the technique described in Japanese Patent No. 2621110 can be used. For example, a TN liquid crystal cell having an amorphous orientation is manufactured. One pixel is defined in a region in the substrate where the transparent electrode (segment electrode) 33 of the segment substrate 30 and the transparent electrode (common electrode) 23 of the common substrate 20 are opposed to each other.

  Reference is made to FIG. A polarizing film-coated substrate 50 is superposed on the segment substrate 30 of the liquid crystal cell so that the polarizing film 54 having a spiral pattern contacts the cell. Further, the polarizing film-coated substrate 60 is superposed on the common substrate 20 in such a direction that the polarizing film 64 having a radial pattern contacts the cell. In the superposition, when the liquid crystal cell is viewed from the normal direction of the substrates 20 and 30, the spiral patterns of the polarizing films 54 and 64 and the centers of the radial patterns coincide with each other, and the center is the pixel. Align so that it is placed outside. Furthermore, the backlight 80 is arrange | positioned at the board | substrate 50 side with a polarizing film of a liquid crystal cell, for example.

  With reference to FIG. 2 (B) and FIG. 3 (B), the arrangement of the polarizing film-coated substrates 50 and 60 will be described in detail. In both figures, a square pattern indicated by a dotted line indicates one pixel (formation position of the segment electrode 33). The polarizing film-coated substrates 50 and 60 are installed at positions where the spiral and radial polarizing film patterns correspond to the pixel patterns of the dot matrix. For example, when viewed from the normal direction of the substrates 20 and 30, the polarizing film-coated substrates 50 and 60 are arranged on the substrates 30 and 20 so that the spiral and radial patterns correspond to the four pixels.

  As shown in FIG. 5E, a schematic cross section of the liquid crystal display element according to the first embodiment is shown between a common substrate 20, a segment substrate 30, and both substrates 20, 30 arranged opposite to each other. It is configured to include the sandwiched liquid crystal layer 40 and the substrates 50 and 60 with polarizing films.

  The common substrate 20 includes a glass substrate 21 and a transparent electrode (common electrode) 23 formed of ITO on the glass substrate 21. The segment substrate 30 includes a glass substrate 31 and a transparent electrode (segment electrode) 33 formed on the glass substrate 31 with ITO. The liquid crystal layer 40 is a TN liquid crystal layer that is amorphously aligned (the alignment state of liquid crystal molecules is random).

  On the surface of the common substrate 20 and the segment substrate 30 opposite to the liquid crystal layer 40, substrates with polarizing films 60 and 50 are disposed, respectively. The substrate 50 with a polarizing film includes a glass substrate 51 and a polarizing film 54 formed on the glass substrate 51. The polarizing film 54 is a metal polarizing film in which a spiral pattern is formed at regular intervals in two orthogonal directions. The polarizing film-coated substrate 60 includes a glass substrate 61 and a polarizing film 64 formed on the glass substrate 61. The polarizing film 64 is a metal polarizing film in which radial patterns are formed at constant intervals equal to the formation interval of the spiral pattern of the polarizing film 54 in two orthogonal directions. The polarizing film-attached substrates 50 and 60 are disposed so that the polarizing films 54 and 64 are in contact with the segment substrates 30 and the glass substrates 31 and 21 of the common substrate 20, respectively. The polarization films 54 and 64 are metal films having a polarization function, and the polarization axes are arranged in a spiral pattern and a radial pattern along the metal line portion (line portion), respectively.

  The backlight 80 is disposed on the polarizing film-coated substrate 50 side of the liquid crystal cell. The liquid crystal display element according to the first embodiment is a normally white mode liquid crystal display element.

  When the liquid crystal display element according to the first embodiment is viewed from the normal direction of the polarizing film-coated substrates 50 and 60, as shown in FIG. 2B and FIG. Each spiral pattern and each radial pattern of the polarizing films 54 and 64 are arranged corresponding to one unit composed of four pixels. The centers of the spiral and radial patterns coincide with each other and are arranged at one point outside the pixel, which is the center of the four pixels.

  FIG. 6 shows an isocontrast curve of the liquid crystal display device according to the first embodiment. The meanings of azimuth angles of 0 °, 90 °, 180 °, 270 ° along the circumferential direction of the circle, and inclination angles of 0 ° to 50 ° along the radial direction of the circle are the same as those in FIG. The display method of the isocontrast curve with the contrast of 10, 20, 50 is the same as in FIG.

  It can be seen that the viewing angle characteristic is extremely wide. The liquid crystal display element according to the first embodiment can realize a good display without inversion display or halftone display when viewed from any orientation and direction.

  With reference to FIGS. 7A to 7E, a method of manufacturing a liquid crystal display device according to the second embodiment will be described. In the liquid crystal display device according to the third embodiment, the polarizing film 54 and the polarizing film 64 are directly formed on the liquid crystal layer 40 side of the segment glass substrate 31 and the common glass substrate 21.

Reference is made to FIG. A Mo film is formed on a transparent substrate, for example, a glass substrate 31 having a thickness of 0.7 mm, and this is patterned to form a polarizing film 54 having a spiral pattern. The formation method, the formation thickness, and the like are the same as those of the polarizing film 54 in the first embodiment. Thereafter, an insulating film 55 is formed on the polarizing film 54. The insulating film 55 can be formed by sputtering, CVD, printing, or the like using a mask formed of SUS, for example. In the second embodiment, SiO ₂ was sputtered using a flexographically-printed resist material as a mask, and an insulating film 55 pattern was formed only on a necessary portion of the polarizing film 54 using a lift-off method.

  Reference is made to FIG. A transparent electrode (segment electrode) 33 having a dot matrix pattern is formed by forming an ITO film on the insulating film 55 and performing patterning or the like by a process similar to the process described with reference to FIGS. Form. Here, when viewed from the normal direction of the glass substrate 31, in explaining the first embodiment, as shown in FIG. 2 (B), it is composed of a total of four dot matrix electrodes, two vertically and two horizontally. Each spiral pattern of the polarizing film 54 is arranged corresponding to one unit. The center of each spiral pattern is arranged at one point outside the dot matrix electrode, which is the center of the four dot matrix electrodes.

  Thus, the segment substrate 30 including the glass substrate 31, the polarizing film 54, the insulating film 55, and the transparent electrode 33 is obtained. Note that a TFT matrix may be formed on the segment substrate 30.

  Refer to FIGS. 7C and 7D. The common substrate 20 is manufactured by a process similar to the process described with reference to FIGS. The common substrate 20 is formed on the glass substrate 21, the polarizing substrate 64 having a radial pattern, the insulating film 65 formed on the polarizing film 64, and the transparent electrode (common) formed on the insulating film 65. Electrode) 23. A color filter pattern can be formed on the common substrate 20.

  An alignment process is performed on the segment substrate 30 and the common substrate 20. At the position corresponding to the pattern of the polarizing film 54 on the segment substrate 30, an orientation process of a spiral circular pattern or a concentric circular pattern is performed. Further, the alignment process of the radial pattern equal to the radial pattern of the polarizing film 64 is performed at a position corresponding to the polarizing film 64 pattern of the common substrate 20. The segment substrate 30 may be subjected to an alignment process of a radial pattern and the common substrate 20 may be subjected to a concentric pattern alignment process. For example, the method described in Patent Document 3 can be used for the alignment treatment. By such an alignment treatment, the liquid crystal molecules of the liquid crystal layer can be spirally aligned.

  Reference is made to FIG. The liquid crystal layer 40 sandwiched between the segment substrate 30 and the common substrate 20 which are arranged to face each other in parallel so that the transparent electrodes 33 and 23 face each other is formed by a liquid crystal dropping injection method (ODF) to produce a liquid crystal cell. A main seal pattern having a closed shape is printed on one substrate, for example, the segment substrate 30, and a gap control agent is sprayed on the other substrate, for example, the common substrate 20. A substrate on which ribs are formed in advance may be used. Then, a predetermined amount of liquid crystal is dropped inside the seal pattern, and both substrates are superposed in a vacuum.

  When the two substrates 20 and 30 are overlapped, the spiral patterns and the radial patterns of the polarizing films 54 and 64 are the same as those in the first embodiment as shown in FIGS. 2B and 3B, for example. Arranged in the same way.

  The backlight 80 is disposed on the segment substrate 30 side of the liquid crystal cell.

  The liquid crystal display element according to the second embodiment thus manufactured is, for example, a normally white mode TN liquid crystal display element.

  FIG. 8 shows isocontrast curves of the liquid crystal display device according to the second embodiment. The meanings of the azimuth angles of 0 °, 90 °, 180 °, 270 ° along the circumferential direction of the circle, and the inclination angle of 0 ° to 50 ° along the radial direction of the circle are the cases in FIGS. Is equal to Further, the display method of the isocontrast curve with the contrast of 10, 20, 50 is the same as that in FIGS.

  It shows an extremely wide viewing angle characteristic, and it can be seen that a display with a high contrast ratio can be obtained from any orientation. In the TN mode liquid crystal display element, it is considered that the highest viewing angle characteristic can be realized.

  In the liquid crystal display elements according to the first and second embodiments, not a stretched film type polarizing plate, but a metal film is patterned into an extremely thin line having a line-to-line distance equal to or less than the wavelength of light. Light is polarized using a polarizing film. For this reason, the reliability of a liquid crystal display element can be improved. In the second embodiment in which the polarizing film is disposed on the liquid crystal layer side of the glass substrate, the reliability is further enhanced because it is not affected by humidity.

  In the liquid crystal display elements according to the first and second embodiments, the polarizing film 54 having a spiral pattern and the polarizing film 64 having a radial pattern are arranged with the liquid crystal layer 40 interposed therebetween. The polarization axes of the polarizing films 54 and 64 are along the lines of each pattern. Since light leakage due to the viewing angle of the polarizing film can be prevented, the viewing angle characteristics of the liquid crystal display element can be dramatically improved. When an alignment treatment corresponding to or similar to the polarizing film pattern is performed, a higher viewing angle improvement effect can be obtained.

  In the embodiment, the change (difference) in the polarization direction within one pixel due to the spiral and radial patterns is about 90 °. By setting the angle at which the polarization axis of the polarizing film shifts within one pixel to 90 °, isotropic viewing angle characteristics can be obtained from any direction. For example, the same effect can be obtained even if the spiral and radial patterns are set as a pair so as to be about 180 °, 270 °, and 360 °. In this case, spirals are more preferable than radials because the aperture ratio can be easily increased.

  In the liquid crystal display elements according to the first and second embodiments, the central portions of the spiral and radial polarizing film patterns are arranged outside the pixels. By adopting such a configuration, there is a problem that it is difficult to obtain a sufficient degree of polarization near the center of the spiral and radial patterns, and when the observation azimuth (viewing angle) is changed, the angle formed by the polarization axis is 90. The problem of easily deviating from the angle can be avoided. In addition, a bright display can be realized by disposing the vicinity of the central portion of the spiral and radial patterns having low light transmittance outside the pixel.

  Since the liquid crystal display elements according to the first and second embodiments have the metal polarizing film 54 between the liquid crystal layer 40 and the backlight 80, the polarized light that does not pass through the polarizing film 54 out of the light emitted from the backlight 80. The component is reflected on the surface of the polarizing film 54 toward the backlight 80 and then re-reflected and reused while depolarizing. For this reason, the liquid crystal display element according to the embodiment can perform display with high luminance.

  Further, in the method for manufacturing the liquid crystal display element according to the first and second embodiments, a technique for transferring a pattern using a high-precision stamper (nanoimprint technique) is used. Once made, the same process as the process for producing the uniaxial polarizing plate can be used. That is, in producing the wire grid type polarizing film, it is only necessary to change the pattern of the mask or stamper, so there is no additional process compared to the case of producing a uniaxial polarizing plate.

  Furthermore, in the liquid crystal display device manufacturing method according to the first and second embodiments, a spiral pattern is used instead of a circle, so that the resist creates a flow in the mold transfer process (pressing process) in the nanoimprint technology. And the possibility of bubbles remaining between the mold and the resist on the glass substrate is significantly reduced. Therefore, it is possible to always produce a good polarizing plate and improve the yield.

  As mentioned above, although this invention was demonstrated along the Example, this invention is not limited to these.

  For example, in the embodiments, a TN liquid crystal display element has been described. However, a vertical alignment liquid crystal display element may be used.

  Moreover, although the Example arrange | positioned the polarizing film of the spiral pattern on the one board | substrate side, and arrange | positions the polarizing film of the radial pattern on the other board | substrate side, it was set as the normally white type liquid crystal display element, A normally black type liquid crystal display element can be obtained by arranging a polarizing film with a spiral pattern on the substrate side or by arranging a polarizing film with a radial pattern on both substrate sides. In the case of a normally black type liquid crystal display element, it is easier to obtain a high contrast ratio when the thickness of the liquid crystal cell is increased to increase the retardation of the liquid crystal layer.

  The polarizing film pattern is not limited to a perfect circular spiral, but may be an elliptical spiral or a spiral polygon. These polygons and ellipses are arranged so as to overlap each other by being enlarged or reduced without being rotated around the pattern center. For example, when combining an elliptical pattern polarizing film and a radial pattern polarizing film, a substantially radial pattern polarizing film orthogonal to each line of the elliptical pattern is formed. When combining a polarizing film with a polygonal pattern and a polarizing film with a radial pattern, a polarizing film with a substantially radial pattern is formed as an assembly of parallel lines orthogonal to each side of the polygonal pattern. For example, when the pixel shape is rectangular, or when the set of dot matrices corresponding to a pair of polarizing film patterns is rectangular, a combination of an elliptical pattern polarizing film and a substantially radial pattern polarizing film is effective. Let's go.

  As described above, when the common substrate 20 or the segment substrate 30 is subjected to an alignment treatment corresponding to or similar to the polarizing film pattern, for example, when the polarizing film has a spiral elliptical pattern, it corresponds to the pattern. When an orientation treatment is performed on the spiral ellipse or concentric ellipse pattern and the orientation state of the liquid crystal molecules is changed to a spiral ellipse or concentric ellipse, a higher viewing angle improvement effect can be obtained. The same applies to the case where the polarizing film pattern has a helical polygonal shape, and an excellent viewing angle improvement effect can be obtained by setting the alignment state of the liquid crystal molecules to the corresponding helical polygonal shape or concentric polygonal shape. When the polarizing film patterns on both the substrates 20 and 30 side are both radial or substantially radial, the alignment process of the liquid crystal molecules is made radial or substantially radial by applying alignment treatment to the corresponding radial or substantially radial pattern. Good.

  In the embodiment, the spiral pattern of the polarizing film is formed with a pattern pitch of 0.2 μm in the radial direction. However, when the line width and the slit width are substantially equal, the pattern pitch is larger than 0.1 μm. , Smaller than 0.4 μm. When the pattern pitch is 0.1 μm or less, the degree of polarization with respect to visible light decreases. Moreover, when it becomes 0.4 micrometer or more, an interference color is observed. The same applies to an elliptical pattern and a polygonal pattern.

  In the manufacturing process of a liquid crystal display element using a stretched film type uniaxial polarizing plate, a process of cutting out a uniaxial polarizing plate and individually sticking it to a liquid crystal cell is necessary. Since the polarizing film is formed on the substrate, the step of attaching the uniaxial polarizing plate is not necessary. Therefore, high production efficiency and low-cost manufacturing can be realized. In particular, when a liquid crystal cell is manufactured by ODF, it is a great advantage.

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

  For example, it can be used for all types of liquid crystal displays such as in-vehicle displays, display for games, mobile phone / DSC displays, audio displays, personal computer monitor displays, liquid crystal TV displays, and mobile TV displays. In particular, it can be suitably used for a liquid crystal display element that requires wide viewing angle display and high reliability.

20 common substrate 21 glass substrate 22 ITO film 23 transparent electrode 30 segment substrate 31 glass substrate 32 ITO film 33 transparent electrode 40 liquid crystal layer 50 substrate with polarizing film
51 glass substrate 52 metal film 53 resist film 54 polarizing film 55 insulating film 60 substrate with polarizing film 61 glass substrate 62 metal film 64 polarizing film 65 insulating films 70a and 70b mask pattern 80 backlight 90 mold 91 silicon substrate 92 thermally oxidized SiO ₂ Film 93 Resist film 95 Chromium film

Claims (6)

A first transparent substrate comprising a first polarizing film having a plurality of spiral patterns or radial patterns, and a first transparent electrode;
A second transparent substrate comprising a second polarizing film disposed opposite to the first transparent substrate and having a plurality of spiral patterns or radial patterns, and a second transparent electrode;
A liquid crystal layer sandwiched between the first transparent substrate and the second transparent substrate;
When viewed from the normal direction of the first and second transparent substrates,
A pixel is defined at a position where the first transparent electrode and the second transparent electrode face each other,
A liquid crystal display element in which the center of the spiral pattern or radial pattern of the first polarizing film coincides with the center of the spiral pattern or radial pattern of the second polarizing film and is arranged outside the pixel .   The liquid crystal display element according to claim 1, wherein the spiral pattern of the first or second polarizing film is a spiral pattern, an elliptical pattern, or a polygonal pattern. 3. The liquid crystal display element according to claim 1, wherein a pattern pitch along a radial direction of the spiral pattern of the first or second polarizing film is larger than 0.1 μm and smaller than 0.4 μm. (A) a first transparent substrate on which a first transparent electrode is formed, a second transparent substrate on which a second transparent electrode is formed, and a liquid crystal layer sandwiched between the first and second transparent substrates And a liquid crystal cell in which a pixel is defined at a position where the first transparent electrode and the second transparent electrode face each other when viewed from the normal direction of the first and second transparent substrates. Process,
(B) A first polarizing film having a plurality of spiral patterns or radial patterns is disposed on the first transparent substrate, and a second having a plurality of spiral patterns or radial patterns on the second transparent substrate. A step of disposing a polarizing film of
Wherein in the step (b), wherein when viewed from the first and the normal direction of the second transparent substrate, and the center of the spiral pattern or a radial pattern of the first polarizing film, the spiral of the second polarizing film A method for manufacturing a liquid crystal display element, wherein the center of a pattern or a radial pattern is made coincident and is arranged outside the pixel.   5. The liquid crystal display element according to claim 4, wherein the polarizing film is formed between the transparent substrate and the transparent electrode, and is formed between the transparent electrode via an insulating film. Production method. 6. The method of manufacturing a liquid crystal display element according to claim 4, wherein the spiral or radial pattern of the polarizing film is transferred and formed by a nanoimprint technique.

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