JP2006285220A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device which can obtain normally white display with a good quality which has sufficiently high contrast and has no tone reversal in an intermediate tone. <P>SOLUTION: Liquid crystal molecules are twist-aligned over an angle range of 90°±5°from one substrate toward the other substrate and encapsulated between the substrates to form a twisted nematic type liquid crystal cell 1. A front polarizing plate 2 is provided on a front side outer surface to be on a display viewer side of the liquid crystal cell 1 so that its transmission axis 2a may be positioned in a direction crossing an alignment treatment direction 16a of a lateral aligning film of the front side substrate at an angle of +45°±5° and a rear polarizing plate 3 is provided on the rear side outer surface of the liquid crystal cell 1 so that its transmission axis 3a may be positioned in a direction crossing the alignment treatment direction 16a of the lateral aligning film of the front side substrate at an angle of -45°±5°. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a liquid crystal display element having a liquid crystal layer in which liquid crystal molecules are twist-aligned at an angle of about 90 °.

  Conventionally, a twisted nematic type liquid crystal display element in which liquid crystal molecules of a liquid crystal layer sandwiched between a pair of substrates is twist-oriented from one substrate to the other substrate is known. As shown in Patent Document 1, a TN liquid crystal display element in which liquid crystal molecules are twist-aligned at an angle of approximately 90 ° includes a front side serving as an observation side of a liquid crystal cell including a twisted nematic liquid crystal layer and a side opposite thereto. Polarizers are respectively installed on the rear side.

  The pair of polarizing plates is positioned in a direction parallel or perpendicular to the alignment treatment direction applied to the alignment film of each substrate of the liquid crystal cell, with the optical axis of either the transmission axis or the absorption axis. In addition, the optical axes of the respective polarizing plates are arranged parallel or orthogonal to each other. The liquid crystal display element in which the optical axes of the respective polarizing plates are arranged in parallel to each other provides a dark display in which light transmission is substantially blocked in a state where no electric field is applied to the liquid crystal layer (normally state). (Normally black display). In addition, a liquid crystal display element in which the optical axes of the respective polarizing plates are arranged so as to be orthogonal to each other can provide a bright display (normally white display) in which light transmission is maximized in a normally state.

In normally white display, a dark display can be obtained by applying a sufficiently strong electric field to the liquid crystal layer to raise the liquid crystal molecules in the vertical direction of the substrate and releasing the twist alignment state.
Japanese Patent Laid-Open No. 6-88962

  However, in the normally white display, in the vicinity of the alignment film provided to regulate the alignment of the liquid crystal molecules on the inner surface of each substrate in contact with the liquid crystal, the alignment is controlled by the alignment process in which the liquid crystal molecules are applied to the alignment film. Due to the so-called anchoring effect that suppresses the behavior of the liquid crystal molecules due to the strong force, the above-mentioned electric field application (on time) causes a decrease in contrast and gradation inversion in the intermediate gradation, and so on. Incurs quality degradation.

  An object of the present invention is to provide a liquid crystal display element capable of obtaining a normally white display of good quality with sufficiently high contrast and no gradation inversion at intermediate gradations.

  A liquid crystal display element according to a first aspect of the present invention is disposed so as to face a first substrate on which at least one electrode is formed, and a surface of the first substrate on which the electrode is formed. A second substrate having at least one electrode opposed to the electrode formed on a surface opposed to the substrate, and an inner surface formed with the electrode formed on the first substrate in a predetermined first direction. A second direction intersecting the first alignment film subjected to the alignment treatment and the inner surface of the second substrate on which the electrodes are formed at an angle of substantially 90 ° with respect to the first direction. Sandwiched between a second alignment film subjected to an alignment treatment, the first alignment film of the first substrate, and the second alignment film of the second substrate, When no electric field is applied between the second electrodes, the liquid crystal molecules are directed from the first alignment film to the second alignment film. A liquid crystal layer that is twist-aligned in a predetermined direction and generates a retardation of substantially λ / 2 with respect to transmitted light, and the first and second substrates disposed opposite to each other, outside the first substrate When a sufficiently strong electric field is applied between the first and second electrodes, either the transmission axis or the absorption axis in the third direction in which the liquid crystal molecules in the vicinity of the first alignment film are aligned The first polarizing plate is disposed outside the second substrate of the first and second substrates disposed opposite to each other, with the first polarizing plate disposed substantially coincident with one of the optical axes. And a second polarizing plate arranged so that either the transmission axis or the absorption axis is substantially orthogonal to the optical axis of the plate.

  A liquid crystal display element according to a second aspect of the present invention is disposed so as to face a first substrate on which at least one electrode is formed and a surface of the first substrate on which the electrode is formed. A second substrate in which at least one electrode facing the electrode is formed on a surface facing the substrate, and an inner surface of the first substrate on which the electrode is formed in the left-right direction as viewed from the observation side. The first direction is formed on the inner surface of the second substrate on which the electrodes are formed, and the first alignment film is aligned in a first direction substantially inclined at 45 ° with respect to a horizontal line. , A second alignment film that has been subjected to an alignment process in a second direction substantially intersecting at 90 °, the first alignment film of the first substrate, and the second alignment film of the second substrate. Liquid crystal molecules when sandwiched between two alignment films and no electric field is applied between the first and second electrodes. A liquid crystal layer that is twist-aligned substantially at 90 ° from the first alignment film toward the second alignment film to generate a retardation of λ / 2 with respect to transmitted light; Direction of alignment film treatment applied to the alignment film of the adjacent substrate between the polarizing plate and the first substrate, and between the second polarizing plate and the second substrate, respectively. A pair of viewing angle compensation films composed of a discotic liquid crystal layer disposed substantially parallel to the first substrate and the first and second substrates disposed opposite to each other, and disposed outside the first substrate, When a sufficiently strong electric field is applied between the first and second electrodes, the optical axis of either the transmission axis or the absorption axis is set in the third direction in which the liquid crystal molecules in the vicinity of the first alignment film are aligned. Opposing each other with the first polarizing plate arranged substantially coincident The first and second substrates are disposed outside the second substrate, and the optical axis of either the transmission axis or the absorption axis is substantially orthogonal to the optical axis of the first polarizing plate. And a second polarizing plate arranged in such a manner.

  Furthermore, a liquid crystal display element according to a third aspect of the present invention is disposed so as to face a first substrate on which at least one electrode is formed and a surface of the first substrate on which the electrode is formed, A second substrate in which at least one electrode facing the electrode is formed on a surface facing the first substrate, and an inner surface of the first substrate on which the electrode is formed are left and right as viewed from the observation side. A first alignment film having been subjected to an alignment treatment in a first direction substantially inclined at 45 ° with respect to a horizontal line of the direction, and an inner surface on which the electrode of the second substrate is formed; A second alignment film subjected to an alignment process in a second direction substantially intersecting at 90 ° with respect to the first direction, the first alignment film of the first substrate, and the second substrate When the electric field is not applied between the first and second electrodes. The crystal molecules are twist-oriented substantially at 90 ° in a predetermined direction from the first alignment film toward the second alignment film, and a retardation of substantially λ / 2 is generated with respect to the transmitted light. Align the optical axes of the liquid crystal layer, the first polarizing plate and the first substrate, and the second polarizing plate and the second substrate, respectively. A pair of viewing angle compensation films composed of a discotic liquid crystal layer disposed substantially parallel to the direction of the applied alignment film treatment, and between the first polarizing plate and the viewing angle compensation film adjacent thereto, And between the second polarizing plate and the viewing angle compensation film adjacent thereto, the optical axis of either the fast axis or the slow axis is substantially the same as the direction of the optical axis of the adjacent viewing angle compensation film. Pair of phases arranged in parallel When a sufficiently strong electric field is applied between the first and second electrodes, the difference plate and the first and second substrates disposed opposite to each other are disposed outside the first substrate. The first polarizing plate arranged with the optical axis of either the transmission axis or the absorption axis substantially coincided with the third direction in which the liquid crystal molecules in the vicinity of the first alignment film are arranged is arranged opposite to each other. The first and second substrates are arranged outside the second substrate, and arranged such that either the transmission axis or the absorption axis is substantially orthogonal to the optical axis of the first polarizing plate. The second polarizing plate is provided.

  According to the liquid crystal display element of the present invention, the liquid crystal layer is placed on the outer surface of the substrate on which the alignment film is provided in the third direction in which the liquid crystal molecules in the vicinity of the alignment film are aligned when a sufficiently high electric field is applied. Since the optical axes of the polarizing plates are aligned, the linearly polarized light incident on the liquid crystal layer when on is transmitted through the liquid crystal layer without being affected by the birefringence due to the alignment of the liquid crystal molecules in the vicinity of the alignment film, and the opposite substrate side Is absorbed by the other polarizing plate arranged with the optical axes orthogonal to each other. As a result, a sufficiently dark dark display can be obtained, so that a normally white display of good quality with high contrast and no inversion of intermediate gradation can be stably obtained.

In the liquid crystal display element according to the first aspect of the present invention, the first polarizing plate is placed in the middle of the twist angle range in which the liquid crystal molecules of the liquid crystal layer are twist-aligned from the first alignment film toward the second alignment film. It is preferable to arrange the optical axis in the third direction which is the direction of the angle.
That is, the first polarizing plate has the first, the first, and the second alignment film formed by an angle that is substantially ½ of an angle formed by the alignment process direction of the first alignment film and the alignment process direction of the second alignment film. The second alignment film is disposed with its optical axis aligned with a third direction rotated from one alignment processing direction to the other. The second alignment film is subjected to an alignment process in a second direction substantially intersecting with the first direction which is an alignment process direction of the first alignment film at 90, and the liquid crystal layer is The liquid crystal molecules are preferably twist-oriented at an angle of 90 ° from the first alignment film toward the second alignment film. In this case, each of the first and second substrates is formed of a rectangular substrate having upper and lower sides extending in the left-right direction and left and right sides extending in the up-down direction when viewed from the observation side. The alignment film is subjected to an alignment process in a direction of approximately 45 ° with respect to a horizontal axis parallel to the upper and lower sides of the rectangular substrate, and the first polarizing plate has its transmission axis perpendicular to the horizontal axis. The second polarizing plate is preferably arranged with its transmission axis parallel to the horizontal axis, and refractive index anisotropy with respect to light transmitted through the liquid crystal layer. Is Δn and the thickness of the liquid crystal layer through which the light is transmitted is d, the product Δn · d is preferably set in the range of 380 nm to 480 nm. As a result, a twisted nematic liquid crystal display element having high display quality and high display quality in which the occurrence of gradation inversion in the intermediate gradation is surely prevented can be obtained. Furthermore, a plurality of color filters for selectively transmitting different wavelength lights are provided for each pixel unit facing each electrode of the first and second substrates, and the pixel unit corresponding to the color filter of different color. It is desirable to set the liquid crystal layer thickness to a different value for each time, and this makes it possible to obtain good color display quality with excellent color reproducibility.

  In the liquid crystal display element according to the first aspect of the present invention, each between the first polarizing plate and the first substrate, and between the second polarizing plate and the second substrate, respectively. It is preferable to further include a pair of viewing angle compensation films made of a discotic liquid crystal layer, the optical axes of which are arranged parallel to the third direction and opposite to each other. Thereby, a high contrast and an effect of suppressing gradation reversal in the intermediate gradation are obtained, and a viewing angle limiting effect for preventing peeping is obtained.

  Further, the optical axes of the first polarizing plate and the first substrate and between the second polarizing plate and the second substrate are respectively applied to the alignment films of the adjacent substrates. It is preferable to further include a pair of viewing angle compensation films made of a discotic liquid crystal layer arranged substantially parallel to the direction of the alignment film treatment. In this case, the product Δn · d of the refractive index anisotropy Δn with respect to the light transmitted through the liquid crystal layer and the layer thickness d is more preferably 450 nm to 550 nm. A reversal suppression effect is obtained and a wide viewing angle is obtained.

  Further, when a pair of viewing angle compensation films are arranged as described above, the first polarizing plate and the viewing angle compensation film adjacent thereto, and the second polarizing plate and the viewing angle compensation adjacent thereto are provided. A pair of retardation plates disposed between the films so that either the optical axis of the fast axis or the slow axis is substantially parallel to the direction of the optical axis of the adjacent viewing angle compensation film, respectively. It is preferable to provide a configuration. In this case, the product Δn · d of the refractive index anisotropy Δn of the liquid crystal layer and the layer thickness d of the liquid crystal layer through which the light is transmitted is set in a range of 350 nm to 450 nm, and the pair of retardation plates It is more preferable that the retardation Re is set in a range of 15 nm to 55 nm, and the first and second substrates are each formed of a rectangular substrate, and the first and second alignment films are More preferably, the orientation treatment is performed in a direction of approximately 45 ° with respect to one side of the rectangular substrate. By arranging the pair of retardation plates in this way, desired high contrast and gradation reversal suppression effect at intermediate gradation can be obtained, and a good display quality with a wider viewing angle can be obtained.

  As in the liquid crystal display element according to the second aspect of the present invention, each optical element is provided between the first polarizing plate and the first substrate, and between the second polarizing plate and the second substrate. Also in the case of a liquid crystal display element having a discotic liquid crystal layer arranged so that its axis is substantially parallel to the direction of the alignment film treatment applied to the alignment film of the adjacent substrate, the first polarizing plate is The alignment treatment direction of the first and second alignment films is substantially ½ of the angle formed by the alignment treatment direction of the first alignment film and the alignment treatment direction of the second alignment film. It is preferable to arrange the optical axes in the third direction rotated from one side to the other side, and the refractive index anisotropy Δn with respect to the light transmitted through the liquid crystal layer and the liquid crystal layer through which the light is transmitted The product Δn · d of the layer thickness d is set in the range of 450 nm to 550 nm. Preferably, the first and second substrates are each formed of a rectangular substrate having upper and lower sides extending in the left-right direction and left and right sides extending in the up-down direction when viewed from the observation side. The second alignment film is preferably subjected to an alignment process in a direction of approximately 45 ° with respect to a horizontal axis parallel to the upper and lower sides of the rectangular substrate. As a result, the desired high contrast and the effect of suppressing gradation inversion in the intermediate gradation can be obtained, and an extremely good display quality with a wider viewing angle can be obtained.

  As in the liquid crystal display element according to the third aspect of the present invention, each between the first polarizing plate and the first substrate and between the second polarizing plate and the second substrate. A pair of viewing angle compensation films composed of a discotic liquid crystal layer disposed so as to be substantially parallel to the direction of alignment film treatment applied to the alignment film of the adjacent substrate, and the first polarizing plate; Either the fast axis or the slow axis is adjacent between the adjacent viewing angle compensation film and between the second polarizing plate and the adjacent viewing angle compensation film. In a liquid crystal display device comprising a pair of retardation plates arranged substantially parallel to the direction of the optical axis of the viewing angle compensation film, the first and second substrates are each constituted by a rectangular substrate. The first and second alignment films are When the orientation treatment is performed in a direction of approximately 45 ° with respect to one side of the rectangular substrate, the refractive index anisotropy of the liquid crystal layer is Δn, and the layer thickness of the liquid crystal layer through which the light is transmitted is d, It is desirable that the product Δn · d is set in the range of 350 nm to 450 nm and the retardation Re of the pair of retardation plates is set in the range of 15 nm to 55 nm. In addition, a plurality of color filters for selectively transmitting light of different wavelengths are provided for each pixel unit facing each electrode of the first and second substrates, and each pixel unit corresponding to a different color filter. It is preferable to set the liquid crystal layer thicknesses to different values, thereby providing a desired high contrast, a tone reversal suppressing effect and a viewing angle characteristic in the intermediate gradation, and excellent color reproducibility. Color display quality can be obtained.

(First embodiment)
FIG. 1 is an exploded plan view showing an optical configuration of a liquid crystal display device as a first embodiment of the present invention, and FIG. 2 is a schematic cross-sectional view showing an enlarged internal configuration thereof.

  The liquid crystal display element of the present embodiment is an active matrix type liquid crystal display element. As shown in FIG. 1, the side 1a parallel to the horizontal axis 1h in the horizontal direction of the liquid crystal display element as viewed from the observation side A liquid crystal cell 1 having a rectangular planar outer shape having a side parallel to the vertical direction perpendicular to the horizontal axis 1h, and the front of the same rectangle installed on the front side and the rear side on the display side across this, It consists of rear polarizing plates 2 and 3.

  In the liquid crystal cell 1, as shown in FIG. 2, a pair of front and rear glass substrates 11 and 12 are joined together with a frame-shaped sealing material (not shown) with a predetermined gap. On the opposing surface (inner surface) of one of the pair of glass substrates 11 and 12 that are bonded, a black mask 13 having openings 13a corresponding to the respective pixel regions is provided.

  On the surface of the front glass substrate 11 facing the rear glass substrate 12, three kinds of color filters 14R, 14G, and 14B of red, green, and blue are arranged in a predetermined manner so as to correspond to the openings 13a of the black mask 13. It is installed in each. Each of these color filters 14R, 14G, and 14B has an area that is larger than the respective openings 13a by an appropriate length over the entire circumference, and is disposed so that the peripheral edge is overlapped with the opening edge of the black mask 13. The thicknesses of the color filters 14R, 14G, and 14B are the liquid crystal layer thicknesses (cell gaps) dr, dg, and db in the respective pixel regions where the color filters 14R, 14G, and 14B are arranged. Each color filter 14R, 14G, 14B is optimally set so that the product of the refractive index anisotropy for each transmitted wavelength light and the layer thickness dr, dg, db substantially match. The optimization of the liquid crystal layer thickness will be described in detail later.

  On the surfaces of the color filters 14R, 14G, and 14B of red, green, and blue having different thicknesses, a common electrode 15 made of a single-layer transparent conductive film that covers them is attached. A front horizontal alignment film 16 that regulates the alignment of liquid crystal molecules is uniformly applied to the surface of the common electrode 15. As shown in FIG. 1, the surface of the front horizontal alignment film 16 is subjected to an alignment process in the direction of an arrow 16a by a rubbing method. This alignment processing direction 16a is a direction that intersects with the horizontal axis 1h parallel to the lower side 1a on the rectangular display surface of the liquid crystal cell 1 at a right angle of −45 ° (clockwise direction is +).

  A plurality of pixel electrodes 17 made of a transparent conductive film are arranged in a matrix arrangement on the inner surface of the rear glass substrate 12 so as to correspond to the openings of the black mask 13 described above. Each pixel electrode 17 is connected to a thin film transistor 18 as an active element. A rear horizontal alignment film 19 is uniformly deposited so as to cover all the pixel electrodes 17 and the thin film transistors 18. Thereafter, as shown in FIG. 1, the horizontal alignment film 19 is subjected to an alignment process by a rubbing method in a direction 19 a perpendicular to the alignment process direction 16 a of the previous horizontal alignment film 16 described above. This alignment processing direction 19a is a direction that intersects with the horizontal axis 1h of the liquid crystal cell 1 in the downward right direction at + 45 °.

  Liquid crystal is sealed to form a liquid crystal layer 110 in spaces where the front and rear horizontal alignment films 16 and 19 are attached to the inner surfaces of both glass substrates 11 and 12 and face each other. The liquid crystal layer 110 is made of nematic liquid crystal having positive dielectric anisotropy, and in the initial state where no electric field is applied, the liquid crystal molecules near the front and rear horizontal alignment films 16 and 19 are respectively The liquid crystal molecules of the liquid crystal layer 110 are twisted between the two glass substrates 11 and 12 by receiving the alignment regulating force along the alignment treatment directions 16a and 19a applied to the rear horizontal alignment films 16 and 19, respectively. Oriented.

  That is, each liquid crystal molecule of the liquid crystal layer 110 is twisted at an angle of 90 ° ± 5 ° in the clockwise direction indicated by the arrow 21 from the surface of the rear horizontal alignment film 19 to the surface of the front horizontal alignment film 16. Arranged. Therefore, the direction indicated by the white arrow 20 rotated by 45 ° clockwise from the alignment processing direction 19a of the rear horizontal alignment film 19 (direction of an intermediate angle in the twist angle range), that is, indicated by this white arrow direction 20 There is a viewing angle direction in which the best contrast is obtained in the liquid crystal display element in the downward direction on the drawing.

  Since the liquid crystal layer 110 in which the liquid crystal molecules are twist-aligned as described above has a wavelength dependency in which the refractive index anisotropy changes depending on the wavelength of transmitted light, color display with high color reproducibility is performed. Further, different liquid crystal layer thicknesses are set for the pixels of the respective colors so as to substantially give a birefringence action of λ / 2 to the red, green, and blue wavelength light transmitted through the liquid crystal layer 110, respectively. .

  That is, in the liquid crystal cell 1 of the present embodiment, the layer thicknesses dr, dg, db for each pixel of red, green, and blue cancel the wavelength dependence of the refractive index anisotropy Δn for each wavelength light. Set to value.

That is, the ratio of refractive index anisotropy Δnb for blue wavelength light, refractive index anisotropy Δng for green wavelength light, and refractive index anisotropy Δnr for red wavelength light is:
Δnb / Δng = 1.04 ± 0.03
Δnr / Δng = 0.96 ± 0.03
Accordingly, as shown in FIG. 2, the liquid crystal layer thickness dr of the pixel in which the red color filter 14R is disposed is 5.5 μm, and the liquid crystal layer thickness of the pixel in which the green color filter 14G is disposed. The film thickness of each color filter 14R, 14G, 14B is set so that dg is 5.0 μm and the liquid crystal layer thickness db of the pixel in which the blue color filter 14B is disposed is 4.8 μm.

  A front polarizing plate 2 is installed on the outer surface of the front glass substrate 11 of the liquid crystal cell 1. As shown in FIG. 1, the front polarizing plate 2 is installed with its transmission axis 2a positioned parallel to the horizontal axis 1h of the display surface when viewed from the observation side. Accordingly, the transmission axis 2a intersects the alignment processing direction 16a applied to the front horizontal alignment film 16 of the liquid crystal cell 1 at an angle of + 45 ° ± 5 °.

  A rear polarizing plate 3 is installed on the outer surface of the rear glass substrate 12 of the liquid crystal cell 1. Thereafter, the polarizing plate 3 has its transmission axis 3a orthogonal to the transmission axis 2a of the front polarizing plate 2, that is, the vertical direction of the display surface (the direction orthogonal to the horizontal axis 1h of the liquid crystal display element as viewed from the observation side). , Hereinafter referred to as the vertical axis direction). Therefore, the transmission axis 3a intersects the alignment processing direction 16a applied to the front horizontal alignment film 16 of the liquid crystal cell 1 at an angle of −45 ° ± 5 °.

  That is, the front polarizing plate 2 has its transmission axis 2a in the middle direction of the twist angle range in which the liquid crystal molecules of the liquid crystal layer are twist aligned from the front horizontal alignment film 16 toward the rear horizontal alignment film 19 (white The absorption axis 2b perpendicular to the transmission axis 2a is arranged substantially in line with the direction of the intermediate angle. The rear polarizing plate 3 has a transmission axis 3a in the middle angle direction of the twist angle range in which the liquid crystal molecules of the liquid crystal layer are twist-oriented from the front horizontal alignment film 16 toward the rear horizontal alignment film 19 ( And the absorption axis 3b orthogonal to the transmission axis 3a is substantially orthogonal to the intermediate angle direction, and the front polarizing plate. The two absorption axes 2b are arranged so as to be substantially orthogonal to each other.

  That is, the front polarizing plate 2 has an angle (45 °) substantially ½ of the angle formed by the alignment treatment direction 19a of the front alignment film 19 and the alignment treatment direction 16a of the rear alignment film 16. Only the transmission axis 2a or the absorption axis 2b is arranged in the direction indicated by the arrow 20 rotated from one alignment processing direction 19a, 16a of the front and rear alignment films 19, 16 toward the other. It is.

  Next, the function and effect of the present liquid crystal display element configured as described above will be described with reference to the schematic explanatory views of FIGS. 3 (a) and 3 (b) and FIGS. 4 (a) and 4 (b). Here, FIGS. 3A and 3B show an initial alignment state of liquid crystal molecules when an electric field is not applied to the liquid crystal layer. FIG. 3A is a plan view, and FIG. 3B is a liquid crystal between substrates. It is sectional drawing which shows the arrangement | sequence state of a molecule | numerator. 4 (a) and 4 (b) show the rising alignment state of the liquid crystal molecules when the electric field is applied to the liquid crystal layer at the maximum, (a) is a plan view, and (b) is the liquid crystal molecules between the substrates. It is sectional drawing which shows an arrangement | sequence state.

  In the initial alignment state shown in FIGS. 3A and 3B, the liquid crystal molecules 110a in the vicinity of both the front and rear horizontal alignment films 16 and 19 receive the alignment regulating force of the corresponding horizontal alignment films 16 and 19, Alignment is performed in such a manner that the major axis direction is aligned with the alignment processing directions 16a and 19a, and the tip end portions on the downstream side of the alignment processing directions 16a and 19a are lifted by the pretilt angle θ. The liquid crystal molecules 110b in the middle of the liquid crystal layer 110 are continuously twist aligned with the alignment of the liquid crystal molecules 110a in the vicinity of the horizontal alignment films 16 and 19 between the substrates. That is, the liquid crystal molecules 110a and 110b are twisted and aligned in the direction of the arrow 21 in the clockwise direction from the one rear horizontal alignment film 19 side to the other front horizontal alignment film 16 side over approximately 90 °. . The liquid crystal layer 110 in which the liquid crystal molecules 110a and 110b are twist-aligned over 90 degrees is set to have birefringence that causes a phase difference of ½ of the wavelength λ of the transmitted light. Therefore, the linearly polarized light transmitted through the liquid crystal layer 110 is emitted as linearly polarized light whose polarization plane is rotated by 90 °.

  In this liquid crystal display element, as shown in FIG. 1, since the transmission axis 3a of the rear polarizing plate 3 and the transmission axis 2a of the front polarizing plate 2 are orthogonal to each other, the absorption axes 3b and 2b are also orthogonal to each other. It is an arrangement. Accordingly, the irradiation light from the backlight (not shown) is transmitted through the rear polarizing plate 3 and is incident on the liquid crystal layer 110 in the initial alignment state with the polarization plane being linearly polarized along the transmission axis 3a. When transmitted, a phase difference of λ / 2 is given, and the polarization plane is rotated 90 ° and emitted. Since the plane of polarization of the outgoing linearly polarized light is along the transmission axis 2a of the front polarizing plate 2, it is transmitted without being absorbed and a bright display is made.

  Next, when a strong electric field is applied to the liquid crystal layer 110 for performing dark display, the liquid crystal molecules 110b positioned in the intermediate layer of the liquid crystal layer 110 are aligned substantially perpendicular to the substrate. The molecular orientation is as shown in FIGS. 4 (a) and 4 (b).

  Each liquid crystal molecule rises and aligns along the major axis in the direction of the applied electric field, that is, the direction perpendicular to the front and rear glass substrates 11 and 12 (see FIG. 2). The liquid crystal molecules 110b located in the middle of the layer thickness direction are aligned substantially vertically and aligned in a state where the spiral is unwound. On the other hand, the liquid crystal molecules 110a in the vicinity of the front and rear horizontal alignment films 16 and 19 cannot sufficiently rise due to the anchoring effect of the corresponding horizontal alignment films 16 and 19, and each horizontal alignment is caused by the intermolecular force that can dissolve the spiral. The liquid crystal molecules 110a in the vicinity of the films 16 and 19 have the pretilt angle θ substantially unchanged and the major axis direction is an intermediate angle in the twist angle range of the twist orientation, that is, the orientation treatment direction 16a of the front orientation film 16 and the orientation treatment of the rear orientation film. The direction of the angle that bisects the angle formed by the direction 19a, that is, the third direction 20 rotated clockwise by 45 ° from the alignment treatment direction 19a of the rear alignment film 19 (the vertical axis of the liquid crystal display element in the drawing) Orientation).

  As the distance from the horizontal alignment films 16 and 19 increases, the rising angle of the liquid crystal molecules 110b increases, and the liquid crystal molecules 110b are aligned substantially vertically in the middle portion of the liquid crystal layer 110. As shown in FIG. 4A, the rising alignment state when the electric field is applied (ON state) is such that each liquid crystal molecule is aligned with its major axis direction substantially aligned with the third direction 20.

  In the present liquid crystal display element, as shown in FIG. 1, the rear polarizing plate 3 is arranged with its transmission axis 3 a along the third direction 20 in the liquid crystal cell 1, so that it is transmitted through the rear polarizing plate 3. When the linearly polarized light transmitted through the liquid crystal layer 110 is not substantially imparted with a phase difference, it is emitted as substantially linearly polarized light. Since the direction of the polarization plane of the outgoing linearly polarized light is the direction along the absorption axis 2b of the front polarizing plate 2, it is reliably absorbed by the front polarizing plate 2 and a good dark display is obtained.

  FIG. 5 is a graph showing the change in transmittance for each wavelength light with respect to the applied voltage of the liquid crystal display element, and the vertical axis indicating the transmittance is a logarithmic scale. As a comparative example, as shown in FIG. 13, a liquid crystal layer is disposed between a pair of opposing substrates, and the alignment treatment direction 131a of the alignment film formed on the rear substrate is set to the horizontal line 131h of the liquid crystal display element. The front and rear polarizing plates 132 and 133 are respectively connected to the transmission axes 132a and 133a in the liquid crystal cell 131 in which the alignment processing direction 131b of the alignment film formed on the front substrate is set to −45 ° with respect to the horizontal line 131h. The two-dot chain line shows the transmittance characteristic of green wavelength light by a conventional TN type liquid crystal display element arranged in the same direction as the alignment processing directions 131a and 131b of the corresponding horizontal alignment film.

  As is clear from FIG. 5, in the liquid crystal display element of this embodiment, the transmittance at the time of applying a maximum electric field with an applied voltage of 4.5 V (on) is 0.02% for green wavelength light, which is the same as the conventional example. Compared to 0.2% of the transmittance at the applied voltage, the transmittance is reduced to about 1/10. As a result, the transmittance when no electric field is applied (off) is substantially the same, so the contrast is about 10 times. It is rising.

  Further, in the conventional TN liquid crystal display element, gradation inversion of intermediate gradation occurs in the direction that coincides with the major axis direction of the liquid crystal molecules. However, in the liquid crystal display element according to the present invention, as described above, Since the transmission axis 3a of the rear polarizing plate 3 coincides with the third direction 20, the occurrence of gradation inversion in the intermediate gradation in the third direction 20 is suppressed.

  As described above, in the liquid crystal display element of the present embodiment, the front polarizing plate 2 and the rear polarizing plate 3 are respectively arranged before and after the liquid crystal cell 1 in which liquid crystal molecules are twist-oriented at an angle of 90 °. The transmission axes 2a and 3a are set orthogonally, and after the backlight is incident, the transmission axis 3a of the polarizing plate 3 is set in a third direction which is an intermediate angle direction in which the liquid crystal molecules are twist-aligned. Since they are arranged so as to coincide with each other, the third direction in which liquid crystal molecules in the vicinity of the alignment film are aligned when the electric field is sufficiently applied and the optical axis composed of the absorption axis or transmission axis of the polarizing plate are substantially parallel. Therefore, a good dark display with a sufficiently low transmittance is obtained, and the display contrast is improved.

  In addition, Δn · d for each pixel provided with the color filters 14R, 14G, and 14B for red, green, and blue respectively has a polarization plane of transmitted light of 90 in consideration of the twist effect due to the twist orientation of liquid crystal molecules. Calculated by an equation (√3 · λ / 2) indicating a retardation value necessary for rotation, and the value was appropriately set in a range of 380 nm to 480 nm for each pixel corresponding to each color filter. Due to the multi-gap structure with the liquid crystal layer thickness, good dark display and high contrast with sufficiently low transmittance can be obtained for wavelength light of all colors. As a result, white with good chromaticity and this are based on this High-quality color display with excellent color reproducibility can be obtained.

In this embodiment, the rear polarizing plate 3 may be arranged with the absorption axis 3 b along the third direction 20. In this case, the front polarizing plate 2 is arranged such that the absorption axis 2b intersects the alignment processing direction 16a at 45 ° ± 5 °. Even with such an arrangement configuration of the optical axes, the desired effect described above is similarly achieved.
(Second Embodiment)

  Next, a second embodiment of the present invention will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected about the component same as the said 1st Embodiment, and the description is abbreviate | omitted.

In addition to the configuration of the liquid crystal display element of the first embodiment, the liquid crystal display element of this embodiment includes a front viewing angle compensation film 4 between the liquid crystal cell 1 and the front polarizing plate 2, and the liquid crystal cell 1 and the rear polarizing plate. 3 and the rear viewing angle compensation film 5 are respectively installed between the two. The multi-gap structure of the liquid crystal cell 1 is the same as that of the first embodiment, and Δn · d of red, green, and blue pixels is appropriately set in the range of 380 nm to 480 nm.
Is set to

  As shown in FIG. 7, the viewing angle compensation films 4 and 5 are formed by forming alignment films 42 and 52 on one surface of transparent film substrates 41 and 51, respectively, and discos on the surfaces of these alignment films 42 and 52. Tick liquid crystal layers 43 and 53 are laminated. The discotic liquid crystal layers 43 and 53 are arranged so that the discotic liquid crystal molecules 43a and 53a are arranged at individual angles while aligning the molecular axes 43b and 53b perpendicular to the disk surface of the liquid crystal molecules in a predetermined direction. Are continuously tilted in one direction, and the directions of the molecular axes 43b and 53b are along the alignment treatment direction applied to the alignment films 42 and 52. The discotic liquid crystal molecules 43a and 53a adjacent to the alignment films 42 and 52 are aligned so that the disk surfaces of the molecules are substantially parallel to the film substrates 41 and 51, and the discotic liquid crystal molecules separated from the surfaces of the alignment films 42 and 52 are provided. As the molecules 43a and 53a move away from the alignment film, the tilt angle of the molecular disk surface with respect to the film substrates 41a and 51a, that is, the tilt angle increases. Accordingly, the discotic liquid crystal layers 43 and 53 have an optical axis (hereinafter referred to as an alignment axis) having a minimum refractive index in a direction in which the inclination angles of the molecular axes 43b and 53b of the discotic liquid crystal molecules 43a and 53a are averaged. The negative optical anisotropy provided is developed.

  In the present embodiment, as shown in FIG. 6, the viewing angle compensation films 4, 5 direct the alignment axes 4 a, 5 a in parallel with the third direction 20 of the liquid crystal cell 1 and in opposite directions to each other. It is installed before and after the cell 1. That is, the orientation axis 4a of the front viewing angle compensation film 4 is aligned with the upper direction of the liquid crystal display element, and the orientation axis 5a of the rear viewing angle compensation film 5 is aligned with the lower direction. It is.

  In the liquid crystal display element of the present embodiment configured as described above, as shown in FIG. 8, the contrast in the left and right visual field direction (9 o'clock to 3 o'clock direction) rapidly decreases as the viewing angle is tilted. That is, when compared at a viewing angle at which the contrast is 10 or less, the liquid crystal display element of the conventional configuration shown in FIG. 13 is 45 ° or more on both the left and right sides, whereas the liquid crystal display element of this embodiment has 15 on both the left and right sides. It is extremely small, such as at least, and is considerably smaller than about 37 ° in the case of the liquid crystal display element of the first embodiment. As for the contrast in the front direction, a high contrast equivalent to that of the liquid crystal display element of the first embodiment is obtained.

  Therefore, according to the liquid crystal display element of the second embodiment, in addition to the color reproducibility obtained by the liquid crystal display element of the first embodiment, the viewing angle in the left and right viewing direction is remarkably narrowed. A useful effect of effectively preventing peeping by others can be obtained.

In addition, it is good also considering the direction of each orientation axis | shaft 4a, 5a of the viewing angle compensation films 4 and 5 as a reverse direction of the direction mentioned above, respectively. That is, even if the orientation axis 4a of the viewing angle compensation film 4 is in the upward direction and the orientation axis 5a of the viewing angle compensation film 5 is in the downward direction, the obtained effect does not change.
(Third embodiment)

  In the liquid crystal display element of the third embodiment, the multi-gap structure of the liquid crystal cell 1 in the liquid crystal display element of the second embodiment is appropriately set so that Δn · d of red, green, and blue pixels is 450 nm to 550 nm, respectively. In addition, the arrangement direction of the orientation axes 4a and 5a of the viewing angle compensation films 4 and 5 is changed.

  That is, as shown in FIG. 9, the front viewing angle compensation film 6 placed between the liquid crystal cell 1 and the front polarizing plate 2 has the discotic liquid crystal molecule alignment axis 6 a aligned in the front horizontal alignment of the liquid crystal cell 1. The film is disposed parallel to the alignment processing direction 16a applied to the film (−45 ° direction with respect to the horizontal axis 1h of the liquid crystal display element), and is disposed between the liquid crystal cell 1 and the rear polarizing plate 3. The rear viewing angle compensation film 7 has the alignment axis 7a of the discotic liquid crystal molecules parallel to the alignment treatment direction 19a applied to the rear horizontal alignment film of the liquid crystal cell 1 (+ 45 ° with respect to the horizontal axis 1h of the liquid crystal display element). (Position).

  According to the liquid crystal display element of the third embodiment configured as described above, the retardation that remains due to the anchoring effect in the liquid crystal layer 110 when turned on is disposed before and after the rear viewing angle compensation film 6. 7, the viewing angle in the lateral direction (horizontal axis direction of the liquid crystal display element) is remarkably improved as compared with the liquid crystal display element of the second embodiment, as shown in FIG. .

  That is, as is apparent from FIG. 10, the liquid crystal display element of the third embodiment has a contrast of about 40 or more in a wide range of both the left and right viewing angles of 80 °, and has the conventional configuration shown in FIG. Compared with a liquid crystal display element, it has a remarkably wide viewing angle characteristic.

  As described above, in the liquid crystal display element of the third embodiment, the alignment axes 6a of the viewing angle compensation films 6 and 7 each including the pair of discotic liquid crystal layers disposed on both the front and rear sides of the liquid crystal cell 1 are interposed. Since the direction of 7a is parallel to the alignment processing directions 16a and 19a of the corresponding horizontal alignment films 16 and 19, the residual retardation when the liquid crystal cell 1 is turned on is effectively compensated, and at least the visual field in the horizontal direction of the display surface The corner is improved. As a result, according to the liquid crystal display element of the third embodiment, in addition to the color display quality with high color reproducibility obtained by the liquid crystal display element of the first embodiment, a good viewing angle that is sufficiently wide in the lateral direction. Characteristics are obtained.

In addition, it is good also considering the direction of each orientation axis | shaft 6a of the viewing angle compensation films 6 and 7 as a reverse direction of the direction mentioned above, respectively. That is, the orientation of the orientation axis 6a of the front viewing angle compensation film 6 is the + 135 ° direction with respect to the horizontal direction 1h and the orientation axis 7a of the rear viewing angle compensation film 7 is the −135 ° direction with respect to the same direction 1h. However, the effect obtained is not changed.
(Fourth embodiment)

  The liquid crystal display element of the fourth embodiment has a multi-gap structure of the liquid crystal cell 1 in the liquid crystal display element of the third embodiment, and the Δn · d values of red, green, and blue pixels are appropriately set in the range of 350 nm to 450 nm. 11, and as shown in FIG. 11, a front retardation plate 8 is provided between the front viewing angle compensation film 16 and the front polarizing plate 2, and a rear viewing angle compensation film 7 and the rear polarizing plate 3 are provided. The rear retardation plates 9 are respectively arranged.

  Both the front and rear retardation plates 8 and 9 are appropriately set so that the product Δn · d of the refractive index anisotropy Δn and the thickness d, that is, the retardation Re is in the range of 15 nm to 55 nm, and the slow axes 8a and 9a are respectively set. I have. The front retardation plate 8 is laminated on the front viewing angle compensation film 6 with its slow axis 8a positioned parallel to the orientation axis 6a of the front viewing angle compensation film 6, and the rear retardation plate 9 has its slow axis. 9a is positioned parallel to the orientation axis 7a of the rear viewing angle compensation film 7 and laminated on the rear viewing angle compensation film.

  According to the liquid crystal display element of the fourth embodiment configured as described above, the retardation compensation effects by the front and rear viewing angle compensation films 6 and 7 are laminated with their optical axes aligned with each other. This is further improved by the front and rear phase difference plates 8 and 9, and the residual retardation at the time of ON is compensated. Therefore, as shown in FIG. The viewing angle characteristics in the direction (horizontal axis direction) are improved.

  That is, as apparent from FIG. 12, a contrast of about 50 or more is secured in a wide range of both left and right viewing angles of 80 °, which is higher than the contrast of 40 or more in the same range by the liquid crystal display element of the third embodiment, The contrast is improved uniformly over the entire viewing angle range except for the vicinity of the front direction.

  As described above, in the liquid crystal display element according to the fourth embodiment, the viewing angle compensation films 6 and 7 including the discotic liquid crystal layers on both the front and rear sides of the liquid crystal cell 1 and the respective retardation plates 8 are provided. 9 is laminated with the respective optical axes aligned in parallel with the alignment processing directions 16a and 19a of the corresponding horizontal alignment films 16 and 19, so that the residual retardation in the liquid crystal cell 1 can be more effectively compensated. The viewing angle is further improved in at least the left and right lateral direction of the display surface. As a result, according to the liquid crystal display element of the fourth embodiment, in addition to the color display quality excellent in color reproducibility obtained by the liquid crystal display element of the first embodiment, at least a viewing angle in the horizontal axis direction is further increased. Widened viewing angle characteristics can be obtained.

  As in the case of the liquid crystal display element of the third embodiment, in the case of the fourth embodiment, the orientation axes 6a and 7a of the viewing angle compensation films 6 and 7 may be opposite to the above-described directions. Well, the effect obtained in that case is not different from the above effect.

  The present invention is not limited to the first to fourth embodiments described above. For example, in the first to fourth embodiments, the arrangement of the transmission axis 3a of the rear polarizing plate 3 is made to coincide with the intermediate angle direction of the twist orientation angle range of the liquid crystal molecules in the liquid crystal cell 1. The transmission axis 3a may be aligned with the third direction in which liquid crystal molecules adjacent to the horizontal alignment film on the corresponding side are aligned when the electric field is sufficiently applied to the liquid crystal layer 110. For example, the third axis Even if the direction is an angle direction about 1/3 of the range of the twist alignment angle of the liquid crystal molecules, the transmission axis 3a of the rear polarizing plate 3 may be made to coincide with this direction.

  The present invention is not limited to a color liquid crystal display element provided with a color filter, but can be effectively applied to a liquid crystal display element that performs monochrome display.

1 is an exploded plan view showing a liquid crystal display element as a first embodiment of the present invention. It is typical sectional drawing which expands partially and shows the internal structure of the said liquid crystal display element. FIG. 2 is an explanatory diagram showing an alignment state of liquid crystal molecules when an electric field is not applied in the liquid crystal display element, in which (a) is a plan view and (b) is a cross-sectional view thereof. It is explanatory drawing which shows the orientation state of the liquid crystal molecule at the time of ON to which the electric field was applied in the said liquid crystal display element, (a) is a top view, (b) is the sectional drawing. It is a graph which shows the change characteristic of the transmittance | permeability with respect to the applied voltage for every wavelength light in the said liquid crystal display element. It is an exploded top view which shows the liquid crystal display element as 2nd Embodiment of this invention. (A) is typical sectional drawing which expands and shows partially the internal structure of the said liquid crystal display element, (b) is the one part sectional drawing. It is a graph which shows the viewing angle characteristic of the left-right direction in the liquid crystal display element as the said 2nd Embodiment. It is a disassembled plan view which shows the liquid crystal display element as 3rd Embodiment of this invention. It is a graph which shows the viewing angle characteristic of the left-right direction in the liquid crystal display element as the said 3rd Embodiment. It is a disassembled top view which shows the liquid crystal display element as 4th Embodiment of this invention. It is a graph which shows the viewing angle characteristic of the left-right direction in the liquid crystal display element as the said 4th Embodiment. It is a disassembled top view which shows the conventional liquid crystal display element.

Explanation of symbols

1, 131 Liquid crystal cell 2, 132 Front polarizing plate 3, 133 Rear polarizing plate 4, 6 Front viewing angle compensation film 5, 7 Rear viewing angle compensation film 8 Front retardation plate 9 Rear retardation plate 11, 12 Glass substrate 13 Black Mask 14R, 14G, 14B Red, green, blue color filter 15 Common electrode 16 Front horizontal alignment film 17 Pixel electrode 18 Thin film transistor 19 Rear horizontal alignment film 110 Liquid crystal layer

Claims (20)

A first substrate on which at least one electrode is formed;
A second substrate that is disposed opposite to the surface of the first substrate on which the electrode is formed, and on which the at least one electrode facing the electrode is formed on the surface facing the first substrate;
A first alignment film in which an alignment process is performed in a predetermined first direction on an inner surface of the first substrate on which the electrode is formed;
A second alignment film having an alignment treatment applied in a second direction substantially intersecting the first direction at an angle of 90 ° to an inner surface of the second substrate on which the electrode is formed; ,
The liquid crystal is sandwiched between the first alignment film of the first substrate and the second alignment film of the second substrate, and an electric field is not applied between the first and second electrodes. A liquid crystal layer in which molecules are twist-oriented in a predetermined direction from the first alignment film toward the second alignment film, and a retardation of substantially λ / 2 is generated with respect to transmitted light;
The first orientation when a sufficiently strong electric field is applied between the first and second electrodes, which are arranged outside the first substrate and the first and second substrates disposed opposite to each other. A first polarizing plate arranged with the optical axis of either the transmission axis or the absorption axis substantially aligned with the third direction in which liquid crystal molecules in the vicinity of the film are arranged;
The first and second substrates disposed opposite to each other are disposed outside the second substrate, and the optical axis of the first polarizing plate is substantially the optical axis of either the transmission axis or the absorption axis. And a second polarizing plate arranged orthogonal to the liquid crystal display element.   The first polarizing plate has a third direction which is an intermediate angle direction of a twist angle range in which the liquid crystal molecules of the liquid crystal layer are twist-oriented from the first alignment film toward the second alignment film. The liquid crystal display element according to claim 1, wherein the liquid crystal display elements are arranged such that their optical axes coincide with each other.   The first polarizing plate has the first and second angles substantially equal to ½ of the angle formed by the alignment treatment direction of the first alignment film and the alignment treatment direction of the second alignment film. The liquid crystal display element according to claim 1, wherein the alignment film is arranged so that the optical axis coincides with a third direction rotated from one alignment processing direction toward the other. The second alignment film is subjected to an alignment process in a second direction substantially intersecting at 90 with respect to a first direction that is an alignment process direction of the first alignment film,
2. The liquid crystal display element according to claim 1, wherein the liquid crystal layer has twist alignment of the liquid crystal molecules at an angle of 90 ° from the first alignment film toward the second alignment film. The first and second substrates are each formed of a rectangular substrate having upper and lower sides extending in the left-right direction as viewed from the observation side and left and right sides extending in the up-down direction, and the first and second alignment films Is subjected to an orientation treatment in a direction of approximately 45 ° with respect to a horizontal axis parallel to the upper and lower sides of the rectangular substrate,
The first polarizing plate is disposed with its transmission axis oriented in a direction perpendicular to the horizontal axis, and the second polarizing plate is disposed with its transmission axis parallel to the horizontal axis. The liquid crystal display element according to claim 4.   When the refractive index anisotropy with respect to the light transmitted through the liquid crystal layer is Δn and the thickness of the liquid crystal layer through which the light is transmitted is d, the product Δn · d is set in the range of 380 nm to 480 nm. The liquid crystal display element according to claim 4, wherein the liquid crystal display element is a liquid crystal display element.   A plurality of color filters for selectively transmitting light of different wavelengths are provided for each pixel unit facing each electrode of the first and second substrates, and for each pixel unit corresponding to a color filter of a different color. The liquid crystal display element according to claim 1, wherein the liquid crystal layer thicknesses are set to different values.   The optical axes are parallel to the third direction and opposite to each other between the first polarizing plate and the first substrate and between the second polarizing plate and the second substrate, respectively. The liquid crystal display element according to claim 1, further comprising a pair of viewing angle compensation films made of a discotic liquid crystal layer disposed toward the surface.   Alignment applied to the alignment films of adjacent substrates between the first polarizing plate and the first substrate and between the second polarizing plate and the second substrate, respectively. The liquid crystal display element according to claim 1, further comprising a pair of viewing angle compensation films made of a discotic liquid crystal layer and arranged substantially parallel to the direction of the film treatment.   When the refractive index anisotropy with respect to the light transmitted through the liquid crystal layer is Δn and the thickness of the liquid crystal layer through which the light is transmitted is d, the product Δn · d is set in the range of 450 nm to 550 nm. The liquid crystal display element according to claim 9.   Either the fast axis or the slow axis between the first polarizing plate and the viewing angle compensation film adjacent thereto and between the second polarizing plate and the viewing angle compensation film adjacent thereto. The liquid crystal display element according to claim 9, further comprising a pair of retardation plates arranged so that their optical axes are substantially parallel to the direction of the optical axis of the adjacent viewing angle compensation film. When the refractive index anisotropy of the liquid crystal layer is Δn and the thickness of the liquid crystal layer through which the light is transmitted is d, their product Δn · d is set in the range of 350 nm to 450 nm,
The liquid crystal display element according to claim 11, wherein the retardation Re of the pair of retardation plates is set in a range of 15 nm to 55 nm.   The first and second substrates are each formed of a rectangular substrate, and the first and second alignment films are subjected to an alignment process in a direction of approximately 45 ° with respect to one side of the rectangular substrate. The liquid crystal display element according to claim 11. A first substrate on which at least one electrode is formed;
A second substrate that is disposed opposite to the surface of the first substrate on which the electrode is formed, and on which the at least one electrode facing the electrode is formed on the surface facing the first substrate;
A first alignment in which an inner surface of the first substrate on which the electrodes are formed is subjected to an alignment process in a first direction substantially inclined at 45 ° with respect to a horizontal line in the horizontal direction when viewed from the observation side. A membrane,
A second alignment film having an alignment treatment applied in a second direction substantially intersecting the first direction at 90 ° on the inner surface of the second substrate on which the electrodes are formed;
The liquid crystal is sandwiched between the first alignment film of the first substrate and the second alignment film of the second substrate, and an electric field is not applied between the first and second electrodes. A liquid crystal layer in which molecules are twist-aligned substantially at 90 ° from the first alignment film toward the second alignment film, and a retardation of substantially λ / 2 is generated with respect to transmitted light;
Alignment applied to the alignment films of adjacent substrates between the first polarizing plate and the first substrate and between the second polarizing plate and the second substrate, respectively. A pair of viewing angle compensation films consisting of a discotic liquid crystal layer disposed substantially parallel to the direction of film treatment;
The first orientation when a sufficiently strong electric field is applied between the first and second electrodes, which are arranged outside the first substrate and the first and second substrates disposed opposite to each other. A first polarizing plate arranged with the optical axis of either the transmission axis or the absorption axis substantially aligned with the third direction in which liquid crystal molecules in the vicinity of the film are arranged;
The first and second substrates disposed opposite to each other are disposed outside the second substrate, and the optical axis of the first polarizing plate is substantially the optical axis of either the transmission axis or the absorption axis. And a second polarizing plate arranged orthogonal to the liquid crystal display element.   The first polarizing plate has the first and second angles substantially equal to ½ of the angle formed by the alignment treatment direction of the first alignment film and the alignment treatment direction of the second alignment film. The liquid crystal display element according to claim 14, wherein the liquid crystal display element is arranged so that an optical axis coincides with a third direction rotated from one of the alignment treatment directions of the alignment film toward the other.   When the refractive index anisotropy with respect to the light transmitted through the liquid crystal layer is Δn and the thickness of the liquid crystal layer through which the light is transmitted is d, the product Δn · d is set in the range of 450 nm to 550 nm. The liquid crystal display element according to claim 14, wherein the liquid crystal display element is a liquid crystal display element.   The first and second substrates are each formed of a rectangular substrate having upper and lower sides extending in the left-right direction as viewed from the observation side and left and right sides extending in the up-down direction, and the first and second alignment films 17. The liquid crystal display element according to claim 16, wherein an alignment process is performed in a direction of approximately 45 degrees with respect to a horizontal axis parallel to the upper and lower sides of the rectangular substrate. A first substrate on which at least one electrode is formed;
A second substrate that is disposed opposite to the surface of the first substrate on which the electrode is formed, and on which the at least one electrode facing the electrode is formed on the surface facing the first substrate;
A first alignment in which an inner surface of the first substrate on which the electrodes are formed is subjected to an alignment process in a first direction substantially inclined at 45 ° with respect to a horizontal line in the horizontal direction when viewed from the observation side. A membrane,
A second alignment film having an alignment treatment applied in a second direction substantially intersecting the first direction at 90 ° on the inner surface of the second substrate on which the electrodes are formed;
The liquid crystal is sandwiched between the first alignment film of the first substrate and the second alignment film of the second substrate, and an electric field is not applied between the first and second electrodes. Liquid crystal in which molecules are twist-aligned substantially at 90 ° in a predetermined direction from the first alignment film toward the second alignment film, and a retardation of substantially λ / 2 is generated with respect to transmitted light. Layers,
Alignment applied to the alignment films of adjacent substrates between the first polarizing plate and the first substrate and between the second polarizing plate and the second substrate, respectively. A pair of viewing angle compensation films consisting of a discotic liquid crystal layer disposed substantially parallel to the direction of film treatment;
Either the fast axis or the slow axis between the first polarizing plate and the viewing angle compensation film adjacent thereto and between the second polarizing plate and the viewing angle compensation film adjacent thereto. A pair of retardation plates arranged so that their optical axes are substantially parallel to the direction of the optical axis of the adjacent viewing angle compensation film,
The first orientation when a sufficiently strong electric field is applied between the first and second electrodes, which are arranged outside the first substrate and the first and second substrates disposed opposite to each other. A first polarizing plate arranged with the optical axis of either the transmission axis or the absorption axis substantially aligned with the third direction in which liquid crystal molecules in the vicinity of the film are arranged;
The first and second substrates disposed opposite to each other are disposed outside the second substrate, and the optical axis of the first polarizing plate is substantially the optical axis of either the transmission axis or the absorption axis. And a second polarizing plate arranged orthogonal to the liquid crystal display element Each of the first and second substrates is a rectangular substrate,
The first and second alignment films are subjected to an alignment process in a direction of approximately 45 ° with respect to one side of the rectangular substrate.
When the refractive index anisotropy of the liquid crystal layer is Δn and the thickness of the liquid crystal layer through which the light is transmitted is d, their product Δn · d is set in the range of 350 nm to 450 nm,
The liquid crystal display element according to claim 18, wherein the retardation Re of the pair of retardation plates is 15 nm to 55 nm.   A plurality of color filters for selectively transmitting light of different wavelengths are provided for each pixel portion facing each electrode of the first and second substrates, and a liquid crystal is provided for each pixel portion corresponding to the color filter of a different color. The liquid crystal display element according to claim 18, wherein the layer thicknesses are set to different values.

Images