JP2006119291A - Liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display wherein reduction of luminance can be suppressed and a visual field angle can be optionally controlled. <P>SOLUTION: The liquid crystal display has an electric field control type panel 3 provided between an array substrate and a backlight unit and including an optical sheet positioned on the array substrate side and a liquid crystal element positioned on the backlight unit side. When mutually orthogonal directions in the surface direction of the electric field control panel are defined as first and second directions, the liquid crystal element emits incident polarized light in the first direction as polarized light in the first or the second direction. The optical sheet emits the polarized light in the first direction while maintaining its polarization direction and dispersing the polarized light and emits the polarized light in the second direction while maintaining its polarization direction and condensing the polarized light in the normal direction of the optical sheet. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a liquid crystal display device.

  In recent years, liquid crystal display devices have been applied to various products such as notebook computers, monitors, car navigation systems, scientific calculators, small and medium-sized TVs, large TVs, mobile phones, and electronic notebooks. Among these products, electronic notebooks, personal digital assistants (PDAs), mobile phones, tablet PCs (PCs), notebook PCs, etc., are liquid crystal display devices that are used in display devices. There are many opportunities to be used. In addition, liquid crystal display devices for ATM (automated teller machine) use and ticket vending machine use are frequently used in public places.

  In the above products, it may be difficult for others to identify the display contents depending on the usage situation. For example, it is a case where private contents are displayed on a mobile phone, PDA, or tablet PC in a public place. In such a case, it is desirable that the viewing angle characteristic of the liquid crystal display device of the above product is narrow. However, since there are also opportunities for a plurality of people to observe the display image, it is desired that the liquid crystal display device has a function of controlling the viewing angle. Not limited to this, it is desired that portable devices and public information terminal devices also have a function of controlling the viewing angle.

In recent years, a detachable louver sheet (for example, a 3M light control film) has been used as a means for controlling the viewing angle of a liquid crystal display device or a cathode ray tube (CRT) (for example, see Patent Document 1). In addition, in a liquid crystal display device using a polarizing plate, a system in which a polarizing plate on the viewer side is not provided and the display can be identified only when polarizing glasses are applied is also applied.
JP 2003-58066 A

  A conventional louver sheet is provided with a light shielding layer having a film thickness of about several millimeters in the normal direction of the sheet in order to sufficiently narrow the viewing angle. For this reason, the method using the louver sheet has a problem that the light transmittance is low and the luminance of the liquid crystal display device is lowered. The louver sheet manufacturing process is complicated and the manufacturing cost is high. There is also a problem that it takes time to attach and detach the louver sheet. In addition, the method using polarized glasses has a problem that a display image cannot be shown to an unspecified person.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a liquid crystal display device capable of suppressing a decrease in luminance and arbitrarily controlling a viewing angle.

  In order to solve the above-described problem, a liquid crystal display device according to an aspect of the present invention is sandwiched between an array substrate, a counter substrate disposed opposite to the array substrate with a gap therebetween, and the array substrate and the counter substrate. A liquid crystal display panel including a liquid crystal layer, a backlight unit provided opposite to the array substrate of the liquid crystal display panel, and an optical device provided between the array substrate and the backlight unit and positioned on the array substrate side An electric field control type panel including a sheet and a liquid crystal element positioned on the backlight unit side, and the first direction and the second direction are plane directions of the electric field control type panel and orthogonal to each other In this case, the liquid crystal element emits polarized light in the first direction incident on the liquid crystal element as polarized light in the first direction or polarized light in the second direction, and the optical sheet. The polarized light in the first direction incident on the optical sheet from the liquid crystal element maintains the polarization direction and scatters and emits the polarized light in the second direction incident on the optical sheet from the liquid crystal element. The polarized light is condensed and emitted in the normal direction of the optical sheet while maintaining the polarization direction.

  A liquid crystal display device according to another aspect of the present invention includes an array substrate, a counter substrate disposed to face the array substrate with a gap therebetween, and a liquid crystal layer sandwiched between the array substrate and the counter substrate. A liquid crystal display panel including: a backlight unit provided opposite to the array substrate of the liquid crystal display panel; and an optical sheet provided between the array substrate and the backlight unit and positioned on both sides of the optical sheet. An electric field control type panel including a pair of liquid crystal elements, and when the first direction and the second direction are plane directions of the electric field control type panel and orthogonal to each other, the backlight unit side The positioned liquid crystal element emits polarized light in the first direction incident on the liquid crystal element as polarized light in the first direction or polarized light in the second direction. From the liquid crystal element located on the backlight unit side, the polarized light in the first direction incident on the optical sheet from the liquid crystal element located on the backlight unit side is scattered and emitted while maintaining the polarization direction. The polarized light in the second direction that is incident on the optical sheet maintains the polarization direction and is condensed and emitted in the normal direction of the optical sheet. The polarized light in the first direction incident on the liquid crystal element from the sheet maintains the polarization direction and scatters and emits the polarized light that is incident on the liquid crystal element from the optical sheet. The direction is reversed to the first direction, and the light is condensed and emitted in the normal direction.

  According to the present invention, it is possible to provide a liquid crystal display device that can suppress a decrease in luminance and can arbitrarily control a viewing angle.

Hereinafter, a liquid crystal display device according to an embodiment of the present invention will be described in detail with reference to the drawings.
As shown in FIGS. 1 to 3, the size of the liquid crystal display device is 15 inches diagonal, and its aspect ratio is 4: 3. The liquid crystal display device is a transmissive type, an MVA type (multi-domain vertical alignment mode) liquid crystal display panel 1, a backlight unit 2 disposed opposite to the liquid crystal display panel at an interval, a liquid crystal display panel and a back surface. An electric field control panel 3 disposed between the light units, a first polarizing plate 4, and a second polarizing plate 5 are provided.

  The liquid crystal display panel 1 includes an array substrate 10, a counter substrate 20, and a liquid crystal layer 30. The array substrate 10 includes a glass substrate 11, a plurality of pixel electrodes 12 formed on the glass substrate, and an alignment film 13 formed on the glass substrate including each pixel electrode. The array substrate 10 has various wirings (not shown) formed on the glass substrate 11, thin film transistors (TFTs) as switching elements, and the like. The counter substrate 20 includes a glass substrate 21, a common electrode 22 formed on the glass substrate, and an alignment film 23 formed on the common electrode. The pixel electrode 12 and the common electrode 22 are formed of a transparent conductive material such as ITO (Indium Tin Oxide). The alignment film 13 and the alignment film 23 are subjected to alignment treatment (rubbing).

  The array substrate 10 and the counter substrate 20 are arranged to face each other with a predetermined gap held by a plurality of spacers 31. The array substrate 10 and the counter substrate 20 are joined to each other by a sealing material 32 disposed at the peripheral edge of both substrates. The liquid crystal layer 30 is sandwiched between the array substrate 10, the counter substrate 20, and the sealing material 32.

  The backlight unit 2 is provided on the outer surface side of the array substrate 10. The backlight unit 2 includes a light guide body 41 including a diffusion plate, a light source 42 disposed opposite to one side edge of the light guide body, and a reflection plate 43. Light incident on the light guide 41 directly from the light source 42 or reflected by the reflector 43 is transmitted through the light guide 41 and emitted from the surface of the light guide as diffused light, that is, backlight light.

  The electric field control panel 3 includes an optical sheet 50, a transparent substrate 60 made of glass or the like disposed opposite to the optical sheet with a predetermined gap, and a liquid crystal element 80 sandwiched between the optical sheet and the transparent substrate. ,have.

  The optical sheet 50 includes an anisotropic medium layer 51 and a transparent isotropic medium layer 52 in close contact with the anisotropic medium layer. The anisotropic medium layer 51 faces the backlight unit 2, and the isotropic medium layer 52 faces the array substrate 10. The liquid crystal element 80 includes a first transparent electrode 81 and an alignment film 82 formed on the anisotropic medium layer 51, a second transparent electrode 83 and an alignment film 84 formed on the transparent substrate 60, an alignment film 82, and A spacer 85 provided between the alignment films 84 and a liquid crystal layer 86 are provided.

  A gap between the alignment film 82 and the alignment film 84 is held by a spacer 85. The liquid crystal layer 86 is sandwiched between the alignment film 82 and the alignment film 84. The anisotropic medium layer 51 and the transparent substrate 60 are bonded to each other by a sealing material (not shown) disposed at the peripheral portions of the alignment film 82 and the alignment film 84.

  The layer thickness of the liquid crystal layer 86 is 4.8 μm. A predetermined chiral material is added to the liquid crystal material constituting the liquid crystal layer 86 so as to obtain the following characteristics. The retardation (Δn) of the liquid crystal material is 0.091 for a wavelength of 550 nm. The twist angle of the liquid crystal molecules is 90 °, and the twist pitch is 60 μm. The twist of the liquid crystal molecules is counterclockwise. As described above, the liquid crystal element 80 is a twisted nematic (TN) type liquid crystal element.

The liquid crystal display panel 1 and the electric field control panel 3 are arranged so that the glass substrate 11 and the isotropic medium layer 52 face each other. The first polarizing plate 4 is disposed on the outer surface of the transparent substrate 60, and the second polarizing plate 5 is disposed on the outer surface of the glass substrate 21. A backlight unit 2 is provided on the outer surface side of the first polarizing plate 4.
The surface direction of the liquid crystal display panel 1 described above, the surface direction of the electric field control panel 3, the surface direction of the first polarizing plate 4, and the surface direction of the second polarizing plate 5 are parallel.

  Next, a more detailed configuration of the optical sheet 50 will be described. Hereinafter, the first direction (X-axis direction) a1 and the second direction (Y-axis direction) a2 are the surface directions of the optical sheet 50 and orthogonal to each other, and the normal direction of the optical sheet 50 is the third direction ( Z axis direction) will be described as a3.

  As shown in FIGS. 3 to 5, the anisotropic medium layer 51 is formed of, for example, a nematic liquid crystal polymer obtained by polymerizing nematic liquid crystal as an optically positive uniaxial refractive index anisotropic medium. . The anisotropic medium layer 51 is formed in a plurality in the first direction a1, and a plurality of arc-shaped convex portions 53 extending in the second direction a2 are formed on the first surface S1. Yes. The optical axis of the anisotropic medium layer 51 is parallel to the second direction a2.

  The isotropic medium layer 52 is formed of, for example, a transparent polymer material as an optically isotropic medium. In the isotropic medium layer 52, a plurality of arc-shaped recesses 54 formed in the first direction a1 and extending in the second direction a2 are formed in the second surface S2. . Here, the above arc shape includes a semicircle and an arc having substantially the same radius of curvature. The anisotropic medium layer 51 and the isotropic medium layer 52 are laminated in a state where the convex portions 53 and the concave portions 54 are in close contact with each other. The anisotropic medium layer 51 has a smooth third surface S3 located on the opposite side of the first surface S1. The isotropic medium layer 52 has a smooth fourth surface S4 located on the opposite side of the second surface S2.

  Each convex portion 53 of the anisotropic medium layer 51 has a center line l. This center line l is a line passing through a plurality of locations of the center c of each convex portion 53. The center line l extends substantially parallel to the second direction a2. In this embodiment, the pitch of the centers c of the plurality of convex portions 53 is 50 μm.

The refractive index nx (1) in the first direction a1 of the anisotropic medium layer 51 is the extraordinary light refractive index ne, and the refractive index ny (1) in the second direction a2 is the ordinary light refractive index no. In this embodiment, when the refractive index of the isotropic medium layer 52 is n (2),
n (2) = nx (1)
The following relational expression is established.

Next, a method for manufacturing the liquid crystal display device will be described.
First, the optical sheet 50 described above is prepared. In this embodiment, the optical sheet 50 has a diagonal size of 15 inches and an aspect ratio of 4: 3. Next, the first transparent electrode 81 is formed of, for example, ITO as a transparent conductive material on the entire surface of the anisotropic medium layer 51 of the optical sheet 50. Thereafter, an alignment film material is applied and baked on the first transparent electrode 81 to form an alignment film 82. Then, the alignment film 82 is rubbed.

  On the other hand, a transparent substrate 60 such as a glass substrate is prepared. A second transparent electrode 83 is formed of, for example, ITO as a transparent conductive material on the entire surface of the prepared transparent substrate 60. Subsequently, a plurality of spacers 85 are formed on the second transparent electrode 83. Thereafter, an alignment film material is applied and baked on the second transparent electrode 83 to form an alignment film 84. Then, the alignment film 84 is rubbed.

  Next, a sealing material is applied to the peripheral portion of the alignment film 84 and the peripheral portions of the alignment film 82 and the alignment film 84 are bonded to each other. Thereby, the transparent substrate 60 and the optical sheet 50 are joined. Here, the alignment film 82 is rubbed in the first direction a1. The alignment film 84 is rubbed in the second direction a2.

  Thereafter, using a vacuum injection method, liquid crystal is injected between the alignment film 82 and the alignment film 84 from a liquid crystal injection port formed in a part of the sealing material. After the liquid crystal is injected, the liquid crystal injection port is sealed with a sealing material (not shown). Thereby, the TN liquid crystal element 80 is completed. In the completed liquid crystal element 80, when no voltage is applied between the first transparent electrode 81 and the second transparent electrode 83, the direction of the major axis of the liquid crystal molecules facing the alignment film 82 is parallel to the first direction a1. .

  Next, the first polarizing plate 4 is bonded to the outer surface of the transparent substrate 60 using, for example, glue. The direction of the transmission axis of the first polarizing plate 4 is the first direction a1. Subsequently, the backlight unit 2 is disposed on the outer surface side of the first polarizing plate 4, and the liquid crystal display panel 1 is disposed on the outer surface side of the isotropic medium layer 52. Here, in the liquid crystal display panel 1, the liquid crystal molecules of the liquid crystal layer 30 are at angles of 45 °, 135 °, 225 °, and 315 ° with the second direction a 2 in a state where a voltage is applied between the pixel electrode 12 and the common electrode 22. It is designed to tilt in the direction of Then, the 2nd polarizing plate 5 is bonded together on the outer surface of the glass substrate 21 of the liquid crystal display panel 1 using glue, for example. The direction of the transmission axis of the second polarizing plate 5 is the first direction a1.

Next, the principle of controlling the viewing angle (backlight light scattering angle) of the liquid crystal display device using the electric field control panel 3 and the first polarizing plate 4 will be described.
First, the control principle in a state where no voltage is applied between the first transparent electrode 81 and the second transparent electrode 83 of the liquid crystal element 80 (an electric field is not applied to the liquid crystal layer 86) will be described.

  As shown in FIG. 6, the first polarizing plate 4 causes the diffused light incident from the backlight unit 2 to be emitted to the liquid crystal element 80 as polarized light in the first direction a1. The liquid crystal element 80 causes the polarized light in the first direction a1 incident on the liquid crystal element to be inverted by 90 ° in the second direction a2 and emitted to the optical sheet 50 as polarized light in the second direction. The optical sheet 50 focuses the polarized light in the second direction a2 incident on the optical sheet from the liquid crystal element 80 in the third direction a3 that maintains the polarization direction and is the normal direction of the optical sheet. Let it emit. That is, the polarized light in the second direction a2 incident on the optical sheet is refracted at the boundary surface between the anisotropic medium layer 51 and the isotropic medium layer 52 and is emitted in the third direction a3.

  From the above, in a state where no voltage is applied between the first transparent electrode 81 and the second transparent electrode 83, the electric field control panel 3 has the polarization direction in the second direction a2 and the third direction a3. The polarized light focused on the light is emitted to the liquid crystal display panel 1.

  Next, the control principle in a state where a voltage is applied between the first transparent electrode 81 and the second transparent electrode 83 of the liquid crystal element 80 (an electric field is applied to the liquid crystal layer 86) will be described.

  As shown in FIG. 7, the first polarizing plate 4 causes diffused light incident from the backlight unit 2 to be emitted to the liquid crystal element 80 as polarized light in the first direction a1. The liquid crystal element 80 maintains the polarization direction and emits the polarized light in the first direction a1 incident on the liquid crystal element to the optical sheet 50 as the polarized light in the first direction a1. The optical sheet 50 causes the polarized light in the first direction a1 incident on the optical sheet from the liquid crystal element 80 to be scattered and emitted while maintaining the polarization direction. That is, the polarized light in the first direction a1 that is incident on the optical sheet travels straight on the boundary surface between the anisotropic medium layer 51 and the isotropic medium layer 52 and is emitted.

  As described above, in a state where a voltage is applied between the first transparent electrode 81 and the second transparent electrode 83, the electric field control panel 3 has the polarization direction in the first direction a1 and the scattered polarization is liquid crystal. The light is emitted to the display panel 1.

  From the explanation of the principle of controlling the viewing angle, it can be seen that the optical sheet 50 has different light collecting properties depending on the polarization direction of polarized light incident on the optical sheet. For this reason, in a state where no voltage is applied between the first transparent electrode 81 and the second transparent electrode 83 of the liquid crystal element 80, the voltage is applied between the pixel electrode 12 and the common electrode 22 in the display mode of the liquid crystal display panel 1. The normally black mode is displayed in black when not being performed. In the state where a voltage is applied between the first transparent electrode 81 and the second transparent electrode 83 of the liquid crystal element 80, the voltage is applied between the pixel electrode 12 and the common electrode 22 in the display mode of the liquid crystal display panel 1. It becomes the normally white mode that becomes white display in the absence.

  From the above, it can be seen that the display mode of the liquid crystal display panel 1 is reversed depending on the presence or absence of a voltage applied between the first transparent electrode 81 and the second transparent electrode 83 of the liquid crystal element 80. Accordingly, when an image is displayed using the liquid crystal display device, the pixel electrode 12 of the liquid crystal display panel 1 and the common electrode are used depending on the presence or absence of a voltage applied between the first transparent electrode 81 and the second transparent electrode 83 of the liquid crystal element 80. The voltage (drive voltage) applied between the electrodes 22 is inverted and displayed.

  Here, the inventor of the present application uses the liquid crystal display device to display an image in two states, a state where a voltage is applied between the first transparent electrode 81 and the second transparent electrode 83 of the liquid crystal element 80 and a state where no voltage is applied. Displayed and examined various display characteristics of luminance viewing angle, contrast viewing angle, front luminance, and front contrast characteristics.

  At that time, the liquid crystal display panel 1 is driven with a driving voltage of 4 V via the TFT, and the liquid crystal element 80 is driven with a driving voltage of 5 V (voltage applied between the first transparent electrode 81 and the second transparent electrode 83). did. Further, the backlight unit 2 was operated and turned on, and the liquid crystal display device was placed in an environment with an illuminance of 0 lx (lux).

First, various characteristics in a state where a voltage is applied to the liquid crystal element 80 (between the first transparent electrode 81 and the second transparent electrode 83) will be described.
A viewing angle having a luminance of 30 cd / m ² or more is as wide as ± 60 ° in the left-right direction, and a viewing angle with a contrast ratio of 10: 1 or more is sufficiently wide as ± 80 ° in the up-down and left-right directions. Further, the front luminance is sufficiently high as 200 cd / m ^2, and it can be seen that the luminance and luminance viewing angle equivalent to those of the liquid crystal display device without the electric field control panel 3 are obtained. The front contrast is sufficiently high at 200: 1.

Next, various characteristics in a state where no voltage is applied to the liquid crystal element 80 (between the first transparent electrode 81 and the second transparent electrode 83) will be described.
The viewing angle having a luminance of 30 cd / m ² or more is sufficiently narrow as ± 10 ° in the left-right direction. The front luminance is 400 cd / m ² and the front contrast is 600: 1. These front luminance and front contrast are higher than those in a structure in which the electric field control panel 3 is not provided or a state in which a voltage is applied to the liquid crystal element 80.

  According to the liquid crystal display device configured as described above, the liquid crystal display device is provided with the electric field control panel 3 between the liquid crystal display panel 1 and the backlight unit 2. The electric field control panel 3 includes an optical sheet 50 and a liquid crystal element 80.

  The optical sheet 50 is formed of an optically uniaxial medium and is formed side by side in the first direction a1, and each of the plurality of arc-shaped convex portions 53 extending in the second direction a2 includes A plurality of anisotropic medium layers 51 formed on one surface S1 and a plurality of optically isotropic media, which are formed side by side in the first direction and extend in the second direction. And an isotropic medium layer 52 formed on the second surface S2. The refractive index n (2) of the isotropic medium layer 52 is equal to the refractive index nx (1) of the anisotropic medium layer 51 in the first direction a1.

  The liquid crystal element 80 includes a first transparent electrode 81 and an alignment film 82 formed on the anisotropic medium layer 51, a second transparent electrode 83 and an alignment film 84 formed on the transparent substrate 60, a liquid crystal layer 86, TN type having

  By switching between two states, a state in which a voltage is applied between the first transparent electrode 81 and the second transparent electrode 83, and a state in which a voltage is not applied, the liquid crystal element 80 is in the first direction a1 incident on the liquid crystal element. Are emitted as polarized light in the first direction or polarized light in the second direction a2. The optical sheet 50 emits the polarized light in the first direction a1 incident on the optical sheet from the liquid crystal element 80 while maintaining the polarization direction and scattering the light, and enters the optical sheet from the liquid crystal element 80. The polarized light in the second direction a2 is condensed and emitted in the third direction a3 while maintaining the polarization direction.

  When displaying an image by narrowing the viewing angle of the liquid crystal display device, display is performed in a state where no voltage is applied between the first transparent electrode 81 and the second transparent electrode 83 of the liquid crystal element 80, and the liquid crystal display device When displaying an image with a wide viewing angle, the image may be displayed with a voltage applied between the first transparent electrode 81 and the second transparent electrode 83 of the liquid crystal element 80. When controlling the viewing angle of the liquid crystal display device, the viewing angle can be easily controlled with a switch or a volume (not shown).

  For this reason, even when used in public places such as mobile PCs, mobile phones, PDAs, electronic notebooks, and tablet PCs, the viewing angle is narrowed if it is difficult for others to identify the display contents. When viewing a display image with a plurality of observers, the viewing angle can be widened. As a result, it is possible to eliminate the worry of others looking into the display contents. It is also possible for a plurality of observers to view the display screen simultaneously and satisfactorily.

  A center line l passing through each convex portion 53 of the anisotropic medium layer 51 extends substantially parallel to the second direction a2. The pitch of the centers c of the plurality of convex portions 53 is 50 μm. For this reason, light (backlight or external light) is hardly diffracted by the optical sheet 50, and the pattern of the convex part 53 of the anisotropic medium layer 51 (the concave part 54 of the isotropic medium layer 52) Cannot be recognized with the naked eye. Even when the optical sheet 50 is provided in the liquid crystal display device, the display quality is not adversely affected. The above effect is effective when the pitch of the centers c of the plurality of convex portions 53 is 10 μm to 70 μm.

  The electric field control panel 3 is provided between the liquid crystal display panel 1 and the backlight unit 2, that is, on the back side of the display screen of the liquid crystal display panel 1. For this reason, it is difficult to visually recognize the pattern of the optical sheet 50 of the electric field control panel 3, and problems such as interference do not occur even when external light is incident.

  The first polarizing plate 4 is provided between the electric field control panel 3 and the backlight unit 2, and the direction of the transmission axis is parallel to the first direction a1. Therefore, the first polarizing plate 4 can emit the backlight light incident on the first polarizing plate to the electric field control panel 3 as the polarized light in the first direction a1.

  The anisotropic medium layer 51 is formed of a material obtained by polymerizing nematic liquid crystal, but may be formed of nematic liquid crystal. The liquid crystal element 80 is a TN type, but may be a birefringence controlled (hereinafter referred to as ECB) type. Since the backlight unit 2 includes the light guide body 41 including the diffusion plate, the scattered light can be emitted.

The liquid crystal display device according to the present embodiment is not provided with a louver sheet. For this reason, the fall of the transmittance | permeability of the backlight light by the light absorption of the louver sheet itself, ie, the brightness | luminance fall, can be prevented. An increase in the thickness of the entire liquid crystal display device can be suppressed, and the manufacturing cost can be reduced.
From the above, it is possible to obtain a liquid crystal display device that can suppress a decrease in luminance and can arbitrarily control the viewing angle.

  Next, a liquid crystal display device according to another embodiment will be described. In this embodiment, the liquid crystal display panel 1 and the backlight unit 2 constituting the liquid crystal display device are configured in the same manner as the liquid crystal display panel and the backlight unit described above. In this embodiment, other configurations are the same as those of the above-described embodiment, and the same portions are denoted by the same reference numerals and detailed description thereof is omitted.

  As shown in FIGS. 8 and 9, the size of the liquid crystal display device is 15 inches diagonal, and its aspect ratio is 4: 3. The liquid crystal display device includes a liquid crystal display panel 1, a backlight unit 2 disposed opposite to the liquid crystal display panel at an interval, an electric field control panel 3 disposed between the liquid crystal display panel and the backlight unit, The first polarizing plate 4, the second polarizing plate 5, and the third polarizing plate 6 are included.

  The electric field control panel 3 includes an optical sheet 50, a transparent substrate 60 and other transparent substrates 70 made of glass or the like disposed opposite to each other with a predetermined gap on both sides of the optical sheet, and between the optical sheet and the transparent substrate. And a liquid crystal element 80 sandwiched between the optical sheet and the other transparent substrate. That is, the electric field control panel 3 has a pair of liquid crystal elements 80 located on both sides of the optical sheet 50.

  The optical sheet 50 includes an anisotropic medium layer 51 and an isotropic medium layer 52 in close contact with the anisotropic medium layer. The anisotropic medium layer 51 faces the backlight unit 2, and the isotropic medium layer 52 faces the array substrate 10. The pair of liquid crystal elements 80 includes a first transparent electrode 81 and an alignment film 82 formed on the optical sheet 50, and a second transparent electrode 83 and an alignment film 84 formed on the transparent substrate 60 or another transparent substrate 70. The spacer 85 provided between the alignment film 82 and the alignment film 84 and the liquid crystal layer 86 are provided.

  In each liquid crystal element 80, the gap between the alignment film 82 and the alignment film 84 is held by a spacer 85. The liquid crystal layer 86 is sandwiched between the alignment film 82 and the alignment film 84. The anisotropic medium layer 51 and the transparent substrate 60, and the isotropic medium layer 52 and the other transparent substrate 70 are bonded to each other by a sealing material (not shown) disposed at the peripheral portions of the alignment film 82 and the alignment film 84. Yes.

The thickness of each liquid crystal layer 86 is 4.8 μm.
A predetermined chiral material is added to the liquid crystal material constituting the liquid crystal layer 86 located on the backlight unit 2 side so as to obtain the following characteristics. The Δn of the liquid crystal material is 0.091 for a wavelength of 550 nm. The twist angle of the liquid crystal molecules is 90 °, and the twist pitch is 60 μm. The twist of the liquid crystal molecules is counterclockwise. From the above, the liquid crystal element 80 located on the backlight unit 2 side is a TN liquid crystal element.

  A predetermined chiral material is added to the liquid crystal material constituting the liquid crystal layer 86 located on the array substrate 10 side so as to obtain the following characteristics. The Δn of the liquid crystal material is 0.091 for a wavelength of 550 nm. The twist angle of the liquid crystal molecules is 90 °, and the twist pitch is 60 μm. The twist of the liquid crystal molecules is clockwise. From the above, the liquid crystal element 80 located on the array substrate 10 side is a TN liquid crystal element.

The liquid crystal display panel 1 and the electric field control panel 3 are arranged so that the glass substrate 11 and the other transparent substrate 70 face each other. The first polarizing plate 4 is disposed on the outer surface of the transparent substrate 60, the second polarizing plate 5 is disposed on the outer surface of the glass substrate 21, and the third polarizing plate 6 is disposed on the outer surface of the glass substrate 11. . A backlight unit 2 is provided on the outer surface side of the first polarizing plate 4.
The surface direction of the liquid crystal display panel 1, the surface direction of the electric field control panel 3, the surface direction of the first polarizing plate 4, the surface direction of the second polarizing plate 5, and the surface direction of the third polarizing plate 6 are parallel. .

Next, a method for manufacturing the liquid crystal display device will be described.
First, the optical sheet 50 described above is prepared. In this embodiment, the optical sheet 50 has a diagonal size of 15 inches and an aspect ratio of 4: 3. Next, first transparent electrodes 81 are formed of, for example, ITO as a transparent conductive material on the entire surface of the anisotropic medium layer 51 and the entire surface of the isotropic medium layer 52 of the optical sheet 50. Thereafter, an alignment film material is applied and baked on each first transparent electrode 81 to form alignment films 82, respectively. Then, each alignment film 82 is rubbed.

  On the other hand, a transparent substrate 60 such as a glass substrate and another transparent substrate 70 are prepared. A second transparent electrode 83 is formed of, for example, ITO as a transparent conductive material on the entire surface of the prepared transparent substrate 60 and the entire surface of the other transparent substrate 70. Subsequently, a plurality of spacers 85 are formed on each second transparent electrode 83. Thereafter, an alignment film material is applied and baked on each second transparent electrode 83 to form an alignment film 84. Then, each alignment film 84 is rubbed.

  Next, a sealing material is applied to the peripheral portion of each alignment film 84, and the peripheral portions of the alignment film 82 and the alignment film 84 are bonded to each other. Thereby, the transparent substrate 60 and the optical sheet 50, and the other transparent substrate 70 and the optical sheet are bonded to each other. Here, each alignment film 82 is rubbed in the first direction a1. Each alignment film 84 is rubbed in the second direction a2.

  Thereafter, using a vacuum injection method, liquid crystal is injected between the alignment films 82 and the alignment films 84 from a liquid crystal injection port formed in a part of the sealing material. After the liquid crystal is injected, the liquid crystal injection port is sealed with a sealing material (not shown). Thereby, a pair of TN liquid crystal elements 80 is completed. In the completed pair of liquid crystal elements 80, when no voltage is applied between the first transparent electrode 81 and the second transparent electrode 83, the major axis direction of the liquid crystal molecules facing each alignment film 82 is parallel, It faces the first direction a1.

  Next, the first polarizing plate 4 is bonded to the outer surface of the transparent substrate 60 using, for example, glue. The direction of the transmission axis of the first polarizing plate 4 is the first direction a1. Subsequently, the backlight unit 2 is disposed on the outer surface side of the first polarizing plate 4, and the liquid crystal display panel 1 is disposed on the outer surface side of the isotropic medium layer 52. Here, in the liquid crystal display panel 1, the liquid crystal molecules of the liquid crystal layer 30 are at angles of 45 °, 135 °, 225 °, and 315 ° with the second direction a 2 in a state where a voltage is applied between the pixel electrode 12 and the common electrode 22. It is designed to tilt in the direction of Then, the 2nd polarizing plate 5 is bonded together on the outer surface of the glass substrate 21 of the liquid crystal display panel 1 using glue, for example. Further, the third polarizing plate 6 is bonded to the outer surface of the glass substrate 11 using, for example, glue. The direction of the transmission axis of the second polarizing plate 5 and the direction of the transmission axis of the third polarizing plate 6 are the first direction a1.

Next, the principle of controlling the viewing angle (backlight light scattering angle) of the liquid crystal display device using the electric field control panel 3 and the first polarizing plate 4 will be described.
First, the control principle in a state where no voltage is applied between the first transparent electrode 81 and the second transparent electrode 83 of each liquid crystal element 80 (an electric field is not applied to the liquid crystal layer 86) will be described.

  As shown in FIG. 10, the first polarizing plate 4 emits diffused light incident from the backlight unit 2 to the liquid crystal element 80 located on the backlight unit 2 side as polarized light in the first direction a1. The liquid crystal element 80 located on the backlight unit 2 side inverts the polarized light in the first direction a1 incident on the liquid crystal element by 90 ° in the second direction a2 and converts the polarized light in the second direction a2 into the optical sheet 50 as polarized light in the second direction. To emit.

  The optical sheet 50 maintains the polarization direction of the polarized light in the second direction a2 incident on the optical sheet from the liquid crystal element 80 located on the backlight unit 2 side, and is the first normal direction of the optical sheet. Light is condensed and emitted in three directions a3. That is, the polarized light in the second direction a2 incident on the optical sheet is refracted at the boundary surface between the anisotropic medium layer 51 and the isotropic medium layer 52 and is emitted in the third direction a3.

  The liquid crystal element 80 positioned on the array substrate 10 side reverses the polarization direction of the condensed polarized light incident on the liquid crystal element from the optical sheet 50 in the first direction a1 and in the third direction a3. Condensed and emitted.

  From the above, in a state where no voltage is applied between each first transparent electrode 81 and each second transparent electrode 83, the electric field control panel 3 has the polarization direction in the first direction a1 and the third direction. The polarized light focused on a3 is emitted to the liquid crystal display panel 1.

  Next, the control principle in a state where a voltage is applied between the first transparent electrode 81 and the second transparent electrode 83 of each liquid crystal element 80 (an electric field is applied to the liquid crystal layer 86) will be described.

  As shown in FIG. 11, the first polarizing plate 4 emits diffused light incident from the backlight unit 2 to the liquid crystal element 80 positioned on the backlight unit 2 side as polarized light in the first direction a1. The liquid crystal element 80 located on the backlight unit 2 side maintains the polarization direction and emits the polarized light in the first direction a1 incident on the liquid crystal element to the optical sheet 50 as the polarized light in the first direction a1.

The optical sheet 50 maintains the polarization direction and scatters and emits the polarized light in the first direction a1 that is incident on the optical sheet from the liquid crystal element 80 located on the backlight unit 2 side. That is, the polarized light in the first direction a1 that is incident on the optical sheet travels straight on the boundary surface between the anisotropic medium layer 51 and the isotropic medium layer 52 and is emitted.
The liquid crystal element 80 positioned on the array substrate 10 side emits the polarized light in the first direction a1 incident on the liquid crystal element from the optical sheet while maintaining the polarization direction and scattering.

From the above, in a state where a voltage is applied between each of the first transparent electrode 81 and the second transparent electrode 83, the electric field control panel 3 has the polarization direction in the first direction a1 and the scattered polarization. The light is emitted to the liquid crystal display panel 1.
From the explanation of the principle of controlling the viewing angle, it can be seen that the optical sheet 50 has different light collecting properties depending on the polarization direction of polarized light incident on the optical sheet.

  As described above, the display mode of the liquid crystal display panel 1 is not reversed regardless of the presence or absence of a voltage applied between the first transparent electrode 81 and the second transparent electrode 83 of each liquid crystal element 80. Therefore, when an image is displayed using the liquid crystal display device, the pixel electrode 12 of the liquid crystal display panel 1 and the liquid crystal display panel 1 can be changed depending on the presence or absence of a voltage applied between the first transparent electrode 81 and the second transparent electrode 83 of each liquid crystal element 80. There is no need to invert and display the voltage (drive voltage) applied between the common electrodes 22.

  Here, the inventor of the present application uses a liquid crystal display device in two ways, a state where a voltage is applied between the first transparent electrode 81 and the second transparent electrode 83 of each liquid crystal element 80 and a state where no voltage is applied. And various display characteristics such as luminance viewing angle, contrast viewing angle, front luminance, and front contrast characteristics were investigated.

  At that time, the liquid crystal display panel 1 is driven at a driving voltage of 4 V via the TFT, and each liquid crystal element 80 is driven at a driving voltage of 5 V (voltage applied between the first transparent electrode 81 and the second transparent electrode 83). Driven. Further, the backlight unit 2 was operated and turned on, and the liquid crystal display device was placed in an environment with an illuminance of 0 lx.

First, various characteristics in a state where a voltage is applied to each liquid crystal element 80 (between the first transparent electrode 81 and the second transparent electrode 83) will be described.
A viewing angle having a luminance of 30 cd / m ² or more is as wide as ± 60 ° in the left-right direction, and a viewing angle with a contrast ratio of 10: 1 or more is sufficiently wide as ± 80 ° in the up-down and left-right directions. Further, the front luminance is sufficiently high as 200 cd / m ^2, and it can be seen that the luminance and luminance viewing angle equivalent to those of the liquid crystal display device without the electric field control panel 3 are obtained. The front contrast is sufficiently high at 600: 1.

Next, various characteristics in a state where no voltage is applied to each liquid crystal element 80 (between the first transparent electrode 81 and the second transparent electrode 83) will be described.
The viewing angle having a luminance of 30 cd / m ² or more is sufficiently narrow as ± 10 ° in the left-right direction. Further, the front luminance is 400 cd / m ² , and a higher value can be obtained than a structure in which the electric field control panel 3 is not provided or a state where a voltage is applied to the liquid crystal element 80. The front contrast is 600: 1.

  According to the liquid crystal display device configured as described above, the liquid crystal display device is provided with the electric field control panel 3 between the liquid crystal display panel 1 and the backlight unit 2. The electric field control panel 3 has an optical sheet 50 and a pair of liquid crystal elements 80 located on both sides of the optical sheet. Each liquid crystal element 80 is a TN type having a first transparent electrode 81 and an alignment film 82, a second transparent electrode 83 and an alignment film 84, and a liquid crystal layer 86.

  By switching between two states, a state in which a voltage is applied between the first transparent electrode 81 and the second transparent electrode 83 of each liquid crystal element 80 and a state in which no voltage is applied, the liquid crystal element 80 positioned on the backlight unit 2 side. Emits polarized light in the first direction a1 incident on the liquid crystal element as polarized light in the first direction or polarized light in the second direction a2.

  The optical sheet 50 maintains the polarization direction and scatters and emits the polarized light in the first direction a1 that is incident on the optical sheet from the liquid crystal element 80 positioned on the backlight unit 2 side. The polarized light in the second direction a2 incident on the optical sheet from the liquid crystal element 80 located on the second side is condensed and emitted in the third direction a3 while maintaining the polarization direction.

  The liquid crystal element 80 positioned on the array substrate 10 side causes the polarized light in the first direction a1 incident on the liquid crystal element from the optical sheet 50 to be output while being scattered and scattered, and from the optical sheet. The condensed polarized light incident on the liquid crystal element is inverted in the polarization direction in the first direction and condensed and emitted in the third direction a3.

  When displaying an image by narrowing the viewing angle of the liquid crystal display device, the display is performed in a state where no voltage is applied between the first transparent electrode 81 and the second transparent electrode 83 of each liquid crystal element 80, and the liquid crystal display device When an image is displayed with a wide viewing angle, the display may be performed with a voltage applied between the first transparent electrode 81 and the second transparent electrode 83 of each liquid crystal element 80. When controlling the viewing angle of the liquid crystal display device, the viewing angle can be easily controlled with a switch or a volume (not shown).

  For this reason, even when used in public places such as mobile PCs, mobile phones, PDAs, electronic notebooks, and tablet PCs, the viewing angle is narrowed if it is difficult for others to identify the display contents. When viewing a display image with a plurality of observers, the viewing angle can be widened. As a result, it is possible to eliminate the worry of others looking into the display contents. It is also possible for a plurality of observers to view the display screen simultaneously and satisfactorily.

  The pair of liquid crystal elements 80 is a TN type. The twisting directions of the liquid crystal molecules facing the alignment film 82 of the liquid crystal element 80 located on the backlight unit 2 side and the liquid crystal molecules facing the alignment film of the liquid crystal element located on the array substrate 10 side are opposite to each other. Therefore, the electric field control panel 3 can emit the light while maintaining the polarization direction at the time of incidence regardless of the wavelength of the polarized light incident on the electric field control panel.

  Further, the pair of liquid crystal elements 80 is not limited to the TN type, but may be an ECB type. In this case, the major axis direction of the liquid crystal molecules facing the alignment film 82 of the liquid crystal element 80 positioned on the backlight unit 2 side and the major axis direction of the liquid crystal molecules facing the alignment film of the liquid crystal element positioned on the array substrate 10 side. Are orthogonal to each other. Each liquid crystal element 80 shifts the phase of polarized light incident on the liquid crystal element by a half wavelength. For this reason, the electric field control panel 3 can emit the polarized light incident on the electric field control panel back to the phase at the time of incidence, and can emit the polarized light in the polarization direction at the time of incidence.

The third polarizing plate 6 is provided between the electric field control panel 3 and the array substrate 10, and the direction of its transmission axis is parallel to the first direction a1. Thereby, since the polarization degree of the polarized light incident on the liquid crystal display panel 1 can be increased, the contrast characteristics can be enhanced. The liquid crystal display device may have a configuration in which the third polarizing plate 6 is not provided, but the provision of the third polarizing plate is advantageous because the contrast characteristics can be enhanced.
From the above, it is possible to obtain a liquid crystal display device that can suppress a decrease in luminance and can arbitrarily control the viewing angle.

  The present invention is not limited to the above-described embodiment, and can be variously modified within the scope of the present invention. For example, in order to reduce the thickness of the entire liquid crystal display device, the first transparent electrode 81 of the liquid crystal element 80 is formed on the optical sheet 50. However, the first transparent electrode 81 is not limited to the optical sheet and is formed on a transparent substrate such as glass. Also good. The optical sheet 50 and the 1st transparent electrode 81 should just be arrange | positioned facing. The liquid crystal display panel 1 is not limited to the transmissive type, and may be a type that displays using the backlight light of the backlight unit 2.

1 is a cross-sectional view of a liquid crystal display device according to an embodiment of the present invention. Sectional drawing which shows the liquid crystal display panel shown in FIG. Sectional drawing which shows the electric field control type panel shown in FIG. The perspective view which shows the optical sheet shown in FIG. FIG. 5 is a perspective view showing the anisotropic medium layer shown in FIGS. 3 and 4. The figure for demonstrating the optical path of the backlight light in the state where the voltage is not applied to the electric field control type panel shown in FIG. 1 and FIG. The figure for demonstrating the optical path of the backlight light in the state where the voltage was applied to the electric field control type panel shown in FIG. 1 and FIG. Sectional drawing of the liquid crystal display device which concerns on other embodiment of this invention. Sectional drawing which shows the electric field control type panel shown in FIG. The figure for demonstrating the optical path of the backlight light in the state where the voltage is not applied to the electric field control type panel shown in FIG. 8 and FIG. The figure for demonstrating the optical path of the backlight light in the state where the voltage was applied to the electric field control type panel shown in FIG. 8 and FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Liquid crystal display panel, 2 ... Backlight unit, 3 ... Electric field control type panel, 4 ... 1st polarizing plate, 5 ... 2nd polarizing plate, 6 ... 3rd polarizing plate, 10 ... Array substrate, 11 ... Glass substrate, DESCRIPTION OF SYMBOLS 12 ... Pixel electrode, 13 ... Orientation film, 20 ... Opposite substrate, 21 ... Glass substrate, 22 ... Common electrode, 23 ... Orientation film, 30 ... Liquid crystal layer, 31 ... Spacer, 32 ... Sealing material, 41 ... Light guide 42 ... Light source, 43 ... Reflector, 50 ... Optical sheet, 51 ... Anisotropic medium layer, 52 ... Isotropic medium layer, 53 ... Convex part, 54 ... Concave part, 60 ... Transparent substrate, 70 ... Transparent substrate, 80 ... Liquid crystal element, 81 ... First transparent electrode, 82 ... Alignment film, 83 ... Second transparent electrode, 84 ... Alignment film, 85 ... Spacer, 86 ... Liquid crystal layer, a1 ... First direction, a2 ... Second direction, a3 ... 3rd direction, c ... center, l ... center line, n1 (x), n1 (y), n2 ... refractive index no ... ordinary refractive index, ne ... extraordinary refractive index, S1, S2, S3, S4 ... surface.

Claims (17)

A liquid crystal display panel, comprising: an array substrate; a counter substrate disposed opposite to the array substrate with a gap; and a liquid crystal layer sandwiched between the array substrate and the counter substrate;
A backlight unit provided facing the array substrate of the liquid crystal display panel;
An electric field control type panel provided between the array substrate and the backlight unit, including an optical sheet positioned on the array substrate side and a liquid crystal element positioned on the backlight unit side,
When the surface direction of the electric field control panel and the directions orthogonal to each other are the first direction and the second direction,
The liquid crystal element emits polarized light in the first direction incident on the liquid crystal element as polarized light in the first direction or polarized light in the second direction,
The optical sheet maintains the polarization direction and scatters and emits polarized light in the first direction incident on the optical sheet from the liquid crystal element and enters the optical sheet from the liquid crystal element. A liquid crystal display device that outputs polarized light in two directions while maintaining the polarization direction and collecting the polarized light in the normal direction of the optical sheet. A liquid crystal display panel, comprising: an array substrate; a counter substrate disposed opposite to the array substrate with a gap; and a liquid crystal layer sandwiched between the array substrate and the counter substrate;
A backlight unit provided facing the array substrate of the liquid crystal display panel;
An electric field control panel provided between the array substrate and the backlight unit and including an optical sheet and a pair of liquid crystal elements positioned on both sides of the optical sheet;
When the surface direction of the electric field control panel and the directions orthogonal to each other are the first direction and the second direction,
The liquid crystal element positioned on the backlight unit side emits polarized light in the first direction incident on the liquid crystal element as polarized light in the first direction or polarized light in the second direction,
The optical sheet causes the polarized light in the first direction incident on the optical sheet from the liquid crystal element located on the backlight unit side to maintain the polarization direction and scatter and emit the polarized light. Polarized light in the second direction that is incident on the optical sheet from the liquid crystal element positioned at the position is maintained in the polarization direction, and is condensed and emitted in the normal direction of the optical sheet,
The liquid crystal element positioned on the array substrate side emits the polarized light in the first direction incident on the liquid crystal element from the optical sheet while maintaining the polarization direction and scattering and emitting the polarized light from the optical sheet. A liquid crystal display device that causes condensed polarized light incident on an element to be reversed in a polarization direction to a first direction and condensed and emitted in the normal direction. The optical sheet is formed of an optically uniaxial medium and is formed side by side in the first direction, and a plurality of arc-shaped convex portions each extending in the second direction are first. An anisotropic medium layer formed on the surface;
A plurality of arc-shaped recesses formed in an optically isotropic medium and arranged in the first direction and extending in the second direction are formed on the second surface. An isotropic medium layer,
The anisotropic medium layer and the isotropic medium layer are laminated in a state where each convex portion and each concave portion are in close contact with each other,
The liquid crystal display device according to claim 1, wherein the anisotropic medium layer is opposed to the backlight unit, and the isotropic medium layer is opposed to the array substrate.   The anisotropic medium layer has a smooth third surface located on the opposite side of the first surface, and the isotropic medium layer is a smooth fourth surface located on the opposite side of the second surface. The liquid crystal display device according to claim 3.   5. The liquid crystal display device according to claim 3, wherein a center line passing through a plurality of locations at the center of each convex portion extends substantially parallel to the second direction.   The liquid crystal display device according to claim 5, wherein a pitch of centers of the plurality of convex portions is 10 μm to 70 μm.   The liquid crystal display device according to claim 3, wherein a refractive index of the isotropic medium layer is equal to a refractive index in the first direction of the anisotropic medium layer.   The liquid crystal display device according to claim 3, wherein the anisotropic medium layer is formed of a nematic liquid crystal or a material obtained by polymerizing the nematic liquid crystal. The liquid crystal element includes a first transparent electrode facing the optical sheet and a first alignment film formed on the first transparent electrode;
A second transparent electrode and a second alignment film formed on the second transparent electrode;
Another liquid crystal layer sandwiched between the first alignment film and the second alignment film,
The liquid crystal element emits polarized light incident in a state where a voltage is applied between the first transparent electrode and the second transparent electrode as polarized light in the first direction, and is incident in a state where no voltage is applied. The liquid crystal display device according to claim 1, wherein the polarized light is emitted as polarized light in the second direction. The pair of liquid crystal elements includes a first transparent electrode facing the optical sheet and a first alignment film formed on the first transparent electrode,
A second transparent electrode and a second alignment film formed on the second transparent electrode;
Each of the liquid crystal layers sandwiched between the first alignment film and the second alignment film,
The liquid crystal element positioned on the backlight unit side emits polarized light that is incident while a voltage is applied between the first transparent electrode and the second transparent electrode of the liquid crystal element as polarized light in the first direction. , The polarized light incident in a state where no voltage is applied is emitted as polarized light in the second direction,
The liquid crystal element positioned on the array substrate side emits polarized light that is incident with a voltage applied between the first transparent electrode and the second transparent electrode of the liquid crystal element as polarized light in the first direction, The liquid crystal display device according to claim 2, wherein polarized light incident in a state where no voltage is applied is emitted as polarized light in the first direction.   The liquid crystal display device according to claim 9, wherein the liquid crystal element is a birefringence control type or a twisted nematic type.   The pair of liquid crystal elements is of a twisted nematic type, facing the first alignment film of the liquid crystal element positioned on the backlight unit side, and facing the first alignment film of the liquid crystal element positioned on the array substrate side The liquid crystal display device according to claim 10, wherein the twisted directions of the liquid crystal molecules are opposite to each other.   The pair of liquid crystal elements is of a birefringence control type, and the major axis direction of the liquid crystal molecules facing the first alignment film of the liquid crystal element positioned on the backlight unit side and the first of the liquid crystal elements positioned on the array substrate side. The liquid crystal display device according to claim 10, wherein the major axis directions of the liquid crystal molecules facing the one alignment film are orthogonal to each other. A polarizing plate provided between the electric field control panel and the backlight unit;
The liquid crystal display device according to claim 1, wherein a direction of a transmission axis of the polarizing plate is parallel to the first direction. Other polarizing plates provided on the outer surface side of the counter substrate,
The liquid crystal display device according to claim 14, wherein a direction of a transmission axis of the other polarizing plate is parallel to the first direction. A first polarizing plate provided between the electric field control panel and the backlight unit;
A second polarizing plate provided on the outer surface side of the counter substrate;
A third polarizing plate provided between the electric field control panel and the array substrate,
The direction of the transmission axis of the first polarizing plate, the direction of the transmission axis of the second polarizing plate, and the direction of the transmission axis of the third polarizing plate are parallel to the first direction, respectively. Or the liquid crystal display device of 13.   The liquid crystal display device according to claim 1, wherein the backlight unit emits scattered light.

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