JPWO2019117310A1 - Liquid crystal display device - Google Patents

Abstract

The liquid crystal display device (1) includes a first display panel (100) including a first liquid crystal cell (10), a second display panel (200) including a second liquid crystal cell (20), and a first display panel (100). ) And the second display panel (200), the first polarizing plate (31) provided on the front surface of the first liquid crystal cell (10), and the second liquid crystal cell (20). A third polarizing plate arranged between the second polarizing plate (32) provided on the back surface, the first liquid crystal cell (10) and the joining member (500), and having a water content of 6 g / m2 or less per unit area. A plate (33) is provided, and the third polarizing plate (33) is provided on the front surface of a polarizing element (33a) made of a polyvinyl alcohol-based film having a thickness of 26 to 30 μm and containing iodine, and a polarizing plate (33a). It also has a first transparent film (33b) made of a triacetyl cellulose-based film that does not contain a phosphoric acid-based plasticizer.

Description

The present disclosure relates to a liquid crystal display device.

A liquid crystal display device using a display panel including a liquid crystal cell is used as a display such as a television or a monitor. However, the liquid crystal display device has a lower contrast ratio than the organic EL (Electro Luminescence) display device.

Therefore, conventionally, a liquid crystal display device capable of achieving a contrast ratio comparable to or higher than that of an organic EL display device by superimposing a plurality of display panels has been proposed (for example, Patent Document 1).

This technology displays a color image on the front side (observer side) display panel and a monochrome image on the back side (backlight side) display panel of the two display panels arranged in the front and back. This is intended to improve the contrast ratio.

In this case, the two display panels are bonded by, for example, a joining member such as an optical transparent adhesive sheet (OCA: Optically Clear Adhesive) or an optical transparent adhesive resin (OCR: Optically Clear Resin).

International Publication No. 2007/040127

However, when a liquid crystal display device in which two display panels are bonded by a joining member (joining layer) is used for a long time, the display screen may be colored. In particular, the central part of the display screen may be colored as if it is brownish. When the display screen is colored in this way, the quality of the displayed image deteriorates.

The present disclosure has been made to solve such a problem, and a liquid crystal display device capable of suppressing deterioration of the quality of a display image even when a plurality of display panels are joined by a joining member such as OCA. The purpose is to provide.

In order to achieve the above object, one aspect of the liquid crystal display device according to the present disclosure is a first display panel including a first liquid crystal cell and a second display panel including the first liquid crystal cell, which is arranged so as to be overlapped with the first display panel. A joining member arranged between the two display panels, the first display panel and the second display panel, and joining the first display panel and the second display panel, and the joining of the first liquid crystal cell. A first polarizing plate provided on a surface opposite to the surface on the member side, a second polarizing plate provided on a surface opposite to the surface on the joining member side of the second liquid crystal cell, and the first polarizing plate. A third polarizing plate arranged between one liquid crystal cell and the joining member and between the second liquid crystal cell and the joining member is provided, and the third polarizing plate includes a polarizing element and a polarizing element. It has a first transparent film provided on the bonding member side of the polarizing element, the polarizing element is a polyvinyl alcohol-based film containing iodine, and the thickness of the polarizing element is 26 μm or more and 30 μm or less. The first transparent film is a triacetyl cellulose-based film that does not contain a phosphoric acid-based plasticizing agent, and the water content per unit area of the third polarizing plate is 6 g / m ² or less.

According to the present disclosure, it is possible to realize a liquid crystal display device capable of suppressing deterioration of the quality of the displayed image.

FIG. 1 is a diagram showing a schematic configuration of a liquid crystal display device according to an embodiment. FIG. 2 is a cross-sectional view of the liquid crystal display device according to the embodiment. FIG. 3 is a diagram showing the change over time in the brownness of the two polarizing plates bonded by OCA. FIG. 4 is a cross-sectional view of the liquid crystal display device according to the modified example.

Hereinafter, embodiments of the present disclosure will be described. It should be noted that all of the embodiments described below show a specific example of the present disclosure. Therefore, the numerical values, shapes, materials, components, the arrangement positions of the components, the connection form, and the like shown in the following embodiments are examples and are not intended to limit the present disclosure. Therefore, among the components in the following embodiments, the components not described in the independent claims indicating the highest level concept of the present disclosure will be described as arbitrary components.

Each figure is a schematic view and is not necessarily exactly illustrated. Therefore, the scales and the like do not always match in each figure. Further, in each figure, the same reference numerals are given to substantially the same configurations, and duplicate description will be omitted or simplified. In addition, in this specification, "abbreviation" or "about" means including manufacturing error and dimensional tolerance.

(Embodiment)
First, the liquid crystal display device 1 according to the embodiment will be described with reference to FIG. FIG. 1 is a diagram showing a schematic configuration of a liquid crystal display device 1 according to an embodiment.

The liquid crystal display device 1 is an example of an image display device in which a plurality of display panels are superposed and arranged in the front-rear direction, and displays a still image or a moving image. In the present embodiment, the liquid crystal display device 1 is composed of two display panels, each including a liquid crystal cell.

As shown in FIG. 1, the liquid crystal display device 1 includes a first display panel 100 and a second display panel 200 arranged so as to overlap the first display panel 100. In the present embodiment, the first display panel 100 is arranged in front of (front side) of the second display panel 200. That is, the second display panel 200 is arranged behind (rear side) of the first display panel 100.

The liquid crystal display device 1 further includes a backlight 300 facing the second display panel 200. Specifically, the backlight 300 is arranged on the back side of the second display panel 200. That is, the second display panel 200 is arranged between the first display panel 100 and the backlight 300, and the first display panel 100, the second display panel 200, and the backlight 300 are arranged from the front to the rear in this order. It is arranged toward.

The first display panel 100 is a main panel arranged at a position closer to the observer (user) than the second display panel 200, and displays an image visually recognized by the observer. In the present embodiment, the first display panel 100 displays a color image.

The first display panel 100 has a first image display area 101 (active area) on which a color image is displayed. The first image display area 101 is composed of a plurality of first pixels arranged in a matrix. The first pixel is composed of a red pixel, a green pixel, and a blue pixel. The first display panel 100 is provided with a first source driver 102 and a first gate driver 103 in order to display a color image in the first image display area 101.

The second display panel 200 is a sub-panel arranged on the back side of the first display panel 100. In the present embodiment, the second display panel 200 displays a monochrome image.

The second display panel 200 has a second image display area 201 (active area) on which a monochrome image is displayed. The second image display area 201 is composed of a plurality of second pixels arranged in a matrix. The second display panel 200 is provided with a second source driver 202 and a second gate driver 203 in order to display a monochrome image in the second image display area 201.

The number of pixels in the first image display area 101 and the number of pixels in the second image display area 201 may be the same or different, but the number of pixels in the first image display area 101 is the first. 2 The number of pixels in the image display area 201 should be larger than the number of pixels. Further, in the present embodiment, the plurality of second pixels in the second image display area 201 are arranged corresponding to the plurality of first pixels in the first image display area 101. Specifically, one second pixel corresponds to three first pixels, a red pixel, a green pixel, and a blue pixel.

The first display panel 100 and the second display panel 200 configured in this way are driven and controlled by, for example, a transverse electric field system such as an IPS (In Plane Switching) system or an FFS (Fringe Field Switching) system. The drive system of the first display panel 100 and the second display panel 200 is not limited to the lateral electric field system, and may be a VA (Vertical Alignment) system, a TN (Twisted Nematic) system, or the like.

The backlight 300 irradiates light toward the first display panel 100 and the second display panel 200. The light emitted from the backlight 300 enters the second display panel 200, passes through the second display panel 200, and then enters the first display panel 100.

In the present embodiment, the backlight 300 is a surface light source unit that irradiates a flat and uniform diffused light (scattered light). The backlight 300 is, for example, an LED backlight using an LED (Light Emitting Diode) as a light source. As an example, the backlight 300 is a direct type backlight in which a plurality of LEDs are arranged two-dimensionally in the row direction and the column direction.

The backlight 300 is not limited to the direct type, but may be an edge type. Further, the light source of the backlight 300 is not limited to the LED, and may be a cold cathode tube or the like. Further, the backlight 300 may have an optical member such as a diffuser plate for diffusing the light from the light source (LED) or a prism sheet for controlling the light distribution of the light.

In the liquid crystal display device 1 of the present embodiment, the second display panel 200 and the first display panel 100 are driven and controlled by the same input video signal (common video source). Specifically, the monochrome image displayed on the second display panel 200 is an image having the same pattern as the color image displayed on the first display panel 100. That is, in the second display panel 200, a monochrome image is displayed in synchronization with the color image of the first display panel 100.

Therefore, the liquid crystal display device 1 includes a first timing controller 410 that controls the first source driver 102 and the first gate driver 103 of the first display panel 100, and the second source driver 202 and the second gate of the second display panel 200. It includes a second timing controller 420 that controls the driver 203, and an image processing unit 430 that outputs image data to the first timing controller 410 and the second timing controller 420.

The image processing unit 430 receives the input video signal Data transmitted from the outside, executes image processing, outputs the first image data DAT1 to the first timing controller 410, and outputs the first image data DAT1 to the second timing controller 420. The image data DAT2 is output. Further, the image processing unit 430 outputs a control signal (omitted in FIG. 1) such as a synchronization signal to the first timing controller 410 and the second timing controller 420. The first image data DAT1 is image data for color display, and the second image data DAT2 is image data for monochrome display. As a result, in the liquid crystal display device 1, the color image and the monochrome image generated by the same input video signal are displayed in synchronization.

As described above, in the liquid crystal display device 1, the two liquid crystal panels of the first display panel 100 and the second display panel 200 are superposed, a color image is displayed on the first display panel 100, and monochrome is displayed on the second display panel 200. The image is displayed. As a result, the monochrome image is superimposed on the color image, so that a color image in which black is tightened can be displayed. Therefore, the contrast ratio can be improved. For example, when the contrast ratio of each display panel of the first display panel 100 and the second display panel 200 is 1000: 1 or more, by superimposing the first display panel 100 and the second display panel 200, 1,000,000: 1 The above high contrast ratio can be realized.

Further, the liquid crystal display device 1 in the present embodiment is an HDR (High Dynamic Range) compatible image display device, and a backlight capable of performing local dimming control is used as the backlight 300. This makes it possible to display a color image having a higher contrast ratio and higher image quality.

Next, the specific structure of the liquid crystal display device 1 will be described with reference to FIG. FIG. 2 is a cross-sectional view showing the configuration of the liquid crystal display device 1 according to the first embodiment. In addition, in FIG. 2, the backlight 300 is schematically represented.

As shown in FIG. 2, the liquid crystal display device 1 includes a joining member 500 that joins the first display panel 100 and the second display panel 200. The joining member 500 is arranged between the first display panel 100 and the second display panel 200. Although the specific structure is not shown, the first display panel 100 and the second display panel 200 joined by the joining member 500 are a metal or resin holding member (frame) together with the backlight 300 as one liquid crystal module. Or it is held in the chassis).

The first display panel 100 and the second display panel 200 are liquid crystal display panels including a liquid crystal cell (liquid crystal panel). Specifically, the first display panel 100 has a first liquid crystal cell 10, a first polarizing plate 31 and a third polarizing plate 33. Further, the second display panel 200 has a second liquid crystal cell 20, a second polarizing plate 32, and a fourth polarizing plate 34.

Since the second display panel 200 is arranged on the back side of the first display panel 100, the second liquid crystal cell 20 of the second display panel 200 is located on the back side of the first liquid crystal cell 10 of the first display panel 100. It is arranged.

The first liquid crystal cell 10 is a first arranged between a first TFT (Thin Film Transistor) substrate 11, a first opposed substrate 12 facing the first TFT substrate 11, and a first TFT substrate 11 and a first opposed substrate 12. It includes a liquid crystal layer 13. In the present embodiment, the first liquid crystal cell 10 is arranged so that the first facing substrate 12 is located in front of the first TFT substrate 11. That is, the first liquid crystal cell 10 is arranged so that the first TFT substrate 11 is located on the backlight 300 side.

The first TFT substrate 11 is a TFT array substrate in which a TFT layer (not shown) is formed on a transparent substrate such as a glass substrate. Although not shown, the TFT layer is formed with a plurality of TFTs provided corresponding to each first pixel of the first image display area 101 (see FIG. 1) and wiring for supplying a voltage to each TFT. Has been done. Further, on the flattening layer of the TFT layer, a pixel electrode for applying a voltage to the first liquid crystal layer 13 is formed. Further, a common electrode facing the pixel electrode is also formed on the first TFT substrate 11. That is, the first TFT substrate 11 includes pixel electrodes and common electrodes that face each other. In the first TFT substrate 11, the TFT, the pixel electrode, and the counter electrode are formed for each pixel, and an alignment film is formed so as to cover the pixel electrode and the counter electrode.

The first opposed substrate 12 is a CF substrate in which a color filter layer is formed as a pixel forming layer on a transparent substrate such as a glass substrate. The pixel forming layer of the first facing substrate 12 has a black matrix in which a plurality of openings corresponding to each of the plurality of first pixels are formed, and a plurality of color filters formed in each opening of the black matrix. .. The black matrix is formed, for example, in a grid pattern. Each of the plurality of color filters is a red color filter corresponding to a red pixel, a green color filter corresponding to a green pixel, or a blue color filter corresponding to a blue pixel, and corresponds to one first pixel. Is formed. An overcoat layer is formed so as to cover the pixel forming layer. In addition, an alignment film is formed on the surface of the overcoat layer.

The first liquid crystal layer 13 is sealed between the first TFT substrate 11 and the first opposed substrate 12. The first liquid crystal layer 13 is sealed by, for example, forming a seal member in a frame shape along the outer peripheral end portions of the first TFT substrate 11 and the first opposed substrate 12. The liquid crystal material of the first liquid crystal layer 13 can be appropriately selected according to the driving method.

The second liquid crystal cell 20 comprises a second TFT substrate 21, a second opposed substrate 22 facing the second TFT substrate 21, and a second liquid crystal layer 23 arranged between the second TFT substrate 21 and the second opposed substrate 22. Be prepared. In the present embodiment, the second liquid crystal cell 20 is arranged so that the second opposed substrate 22 is located in front of the second TFT substrate 21. That is, the second liquid crystal cell 20 is arranged so that the second TFT substrate 21 is located on the backlight 300 side. The second liquid crystal cell 20 may be arranged so that the second TFT substrate 21 is located in front of the second opposed substrate 22.

The second TFT substrate 21 has the same configuration as the first TFT substrate 11, and is a TFT array substrate in which a TFT layer (not shown) is formed on a transparent substrate such as a glass substrate. Although not shown, the TFT layer of the second TFT substrate 21 is provided with TFTs corresponding to the second pixels of the second image display area 201 (see FIG. 1), and wiring for supplying voltage to each TFT. And are formed. Further, the second TFT substrate 21 is also formed with a pixel electrode for applying a voltage to the second liquid crystal layer 23 and a common electrode facing the pixel electrode. That is, the second TFT substrate 21 includes pixel electrodes and common electrodes that face each other. In the second TFT substrate 21, the TFT, the pixel electrode, and the counter electrode are formed for each second pixel, and an alignment film is formed so as to cover the pixel electrode and the counter electrode.

The second opposed substrate 22 is a substrate in which a pixel forming layer is formed on a transparent substrate such as a glass substrate. The pixel forming layer of the second opposed substrate 22 has a black matrix in which a plurality of openings corresponding to each of the plurality of second pixels are formed. The black matrix is formed, for example, in a grid pattern. An overcoat layer is formed so as to cover the pixel forming layer. In addition, an alignment film is formed on the surface of the overcoat layer. In the present embodiment, since the second display panel 200 displays a monochrome image, a color filter is not formed on the pixel forming layer of the second opposed substrate 22. Therefore, the overcoat layer is filled in the opening of the black matrix of the pixel forming layer of the second opposed substrate 22.

The second liquid crystal layer 23 is sealed between the second TFT substrate 21 and the second opposed substrate 22. The second liquid crystal layer 23 is sealed by, for example, forming a seal member in a frame shape along the outer peripheral end portions of the second TFT substrate 21 and the second opposed substrate 22. The liquid crystal material of the second liquid crystal layer 23 can be appropriately selected according to the driving method.

As described above, the liquid crystal display device 1 uses four polarizing plates, a first polarizing plate 31, a second polarizing plate 32, a third polarizing plate 33, and a fourth polarizing plate 34. Specifically, the first polarizing plate 31 and the third polarizing plate 33 are arranged so as to sandwich the first liquid crystal cell 10, and the fourth polarizing plate 34 and the second polarizing plate 32 are arranged so as to sandwich the first liquid crystal cell 10. It is arranged so as to sandwich. Further, the first polarizing plate 31, the third polarizing plate 33, the fourth polarizing plate 34, and the second polarizing plate 32 are arranged in this order from the observer side toward the backlight 300.

In the present embodiment, the first polarizing plate 31 and the second polarizing plate 32 are arranged at positions outside the first liquid crystal cell 10 and the second liquid crystal cell 20.

Specifically, the first polarizing plate 31 is provided on the front surface (the surface on the observer side) of the first liquid crystal cell 10. That is, the first polarizing plate 31 is provided on the surface of the first liquid crystal cell 10 opposite to the surface on the bonding member 500 side. In the present embodiment, the first polarizing plate 31 is attached to the outer surface of the first opposed substrate 12 of the first liquid crystal cell 10 via an adhesive layer.

Further, the second polarizing plate 32 is provided on the back surface (the surface on the backlight 300 side) of the second liquid crystal cell 20. That is, the second polarizing plate 32 is provided on the surface of the second liquid crystal cell 20 opposite to the surface on the bonding member 500 side. In the present embodiment, the second polarizing plate 32 is attached to the outer surface of the second TFT substrate 21 of the second liquid crystal cell 20 via an adhesive layer.

On the other hand, the third polarizing plate 33 and the fourth polarizing plate 34 are arranged between the first liquid crystal cell 10 and the second liquid crystal cell 20. That is, the third polarizing plate 33 and the fourth polarizing plate 34 are sandwiched between the first liquid crystal cell 10 and the second liquid crystal cell 20.

The third polarizing plate 33 is arranged between the first liquid crystal cell 10 and the joining member 500, and between the second liquid crystal cell 20 and the joining member 500, and the fourth polarizing plate 34 is the first. It is arranged on the other side between the 1 liquid crystal cell 10 and the joining member 500 and between the second liquid crystal cell 20 and the joining member 500.

In the present embodiment, the third polarizing plate 33 is arranged between the first liquid crystal cell 10 and the bonding member 500, and the fourth polarizing plate 34 is arranged between the bonding member 500 and the second liquid crystal cell 20. There is.

Specifically, the third polarizing plate 33 is provided on the back surface (the surface on the backlight 300 side) of the first liquid crystal cell 10. That is, the third polarizing plate 33 is provided on the surface of the first liquid crystal cell 10 on the bonding member 500 side. In the present embodiment, the third polarizing plate 33 is attached to the outer surface of the first TFT substrate 11 of the first liquid crystal cell 10 via an adhesive layer.

Further, the fourth polarizing plate 34 is arranged on the front surface (the surface on the observer side) of the second liquid crystal cell 20. That is, the fourth polarizing plate 34 is provided on the surface of the second liquid crystal cell 20 on the bonding member 500 side. In the present embodiment, the fourth polarizing plate 34 is attached to the outer surface of the second opposed substrate 22 of the second liquid crystal cell 20 via the adhesive layer.

Of the four polarizing plates arranged in this way, the first polarizing plate 31 and the third polarizing plate 33 sandwiching the first liquid crystal cell 10 are arranged so that their polarization axes are orthogonal to each other. That is, the first polarizing plate 31 and the third polarizing plate 33 are arranged so as to have a positional relationship of cross Nicols.

Similarly, the fourth polarizing plate 34 and the second polarizing plate 32 sandwiching the second liquid crystal cell 20 are arranged so that their polarization axes are orthogonal to each other. That is, the fourth polarizing plate 34 and the second polarizing plate 32 are arranged so as to have a positional relationship of cross Nicols.

Further, the third polarizing plate 33 and the fourth polarizing plate 34 located between the first liquid crystal cell 10 and the second liquid crystal cell 20 are arranged so that their polarization axes are substantially parallel to each other. Therefore, the first polarizing plate 31 and the second polarizing plate 32 are arranged so that their polarization axes are substantially parallel to each other. Specifically, the absorption axis of the third polarizing plate 33 and the absorption axis of the fourth polarizing plate 34 are substantially parallel, and the absorption axis of the first polarizing plate 31 and the absorption axis of the second polarizing plate 32 are substantially parallel. It has become.

Each of the four polarizing plates of the first polarizing plate 31, the second polarizing plate 32, the third polarizing plate 33, and the fourth polarizing plate 34 is a sheet-shaped polarizing film made of, for example, a resin material, and is a polarizing element and polarized light. Includes a transparent protective film laminated on the child. The polarizer and the transparent protective film are bonded to each other by, for example, an adhesive. Further, in order to protect both sides of the polarizer, a transparent protective film may be provided on each of both sides of the polarizer. That is, the polarizer may be sandwiched between a pair of transparent protective films.

Each of the polarizing elements in the four polarizing plates is, for example, one in which a dichroic substance such as iodine is adsorbed on a resin film and the molecules are oriented by stretching or the like. As the resin film of each polarizer, a polyvinyl alcohol (PVA; polyvinyl alcohol) -based film can be used.

Polyvinyl alcohol (PVA) or a derivative thereof is used as the material of the PVA-based film applied to each polarizer. As the derivative of polyvinyl alcohol, polyvinyl formal, polyvinyl acetal and the like can be used, but in addition, olefins such as ethylene and propylene, unsaturated carboxylic acids such as acrylic acid, methacrylic acid and crotonic acid, alkyl esters thereof, acrylamide and the like can be used. You may use the one modified with. As an example, polyvinyl alcohol having a degree of polymerization of about 1000 to 10000 and a degree of saponification of about 80 to 100 mol% is used.

Further, the PVA-based film constituting each polarizer may contain an additive such as a plasticizer. As the plasticizer, polyols and condensates thereof and the like can be used, and for example, glycerin, diglycerin, triglycerin, ethylene glycol, propylene glycol, polyethylene glycol and the like can be used. The amount of the plasticizer used is not particularly limited, but when the plasticizer is added to the PVA-based film, it is preferable that 20% by weight or less of the plasticizer is added to the PVA-based film.

Further, each of the transparent protective films in the four polarizing plates is composed of a transparent resin material, and functions as a protective film for protecting the polarizer and also as a base film for supporting the polarizer. As the material of the transparent protective film, a cellulose resin such as triacetyl cellulose (TAC), a (meth) acrylic resin, a polyester resin, a polyether sulfone resin, a polysulfone resin, a polycarbonate resin, and a polyamide resin , Polygon-based resin, polyolefin-based resin, cyclic polyolefin-based resin (norbornen-based resin), polyarylate-based resin, polystyrene-based resin, polyvinyl alcohol-based resin, and mixtures thereof can be used.

In the four polarizing plates of the first polarizing plate 31, the second polarizing plate 32, the third polarizing plate 33, and the fourth polarizing plate 34, the configuration of the third polarizing plate 33 and the fourth polarizing plate 34 is the first polarizing plate 31. And the configuration of the second polarizing plate 32 is different.

Specifically, the third polarizing plate 33 is laminated on the polarizer 33a, the first transparent film 33b which is a transparent protective film laminated on one surface of the polarizer 33a, and the other surface of the polarizer 33a. It has a second transparent film 33c, which is a transparent protective film. That is, the polarizer 33a is sandwiched between the first transparent film 33b and the second transparent film 33c.

The polarizer 33a is a PVA-based film containing iodine. The thickness of the polarizer 33a is 26 μm or more and 30 μm or less.

The first transparent film 33b is provided on the bonding member 500 side of the polarizer 33a. Specifically, the first transparent film 33b is bonded to the surface of the polarizer 33a on the bonding member 500 side with an adhesive or the like. The first transparent film 33b is a TAC-based film that does not contain a phosphoric acid-based plasticizer. That is, the phosphoric acid-based plasticizer contained in the TAC-based film, which is the first transparent film 33b, is 0% by weight.

In addition, in this specification, "TAC film which does not contain a phosphoric acid-based plasticizer" means that the TAC-based film does not intentionally contain a phosphoric acid-based plasticizer. Therefore, when a trace amount of phosphoric acid-based plasticizer is unintentionally contained in the TAC-based film as an impurity, it is included in the concept of "TAC-based film not containing the phosphoric acid-based plasticizer".

The second transparent film 33c is provided on the side opposite to the bonding member 500 side (first liquid crystal cell 10 side) of the polarizer 33a. Specifically, the second transparent film 33c is attached to the surface of the polarizer 33a on the first liquid crystal cell 10 side with an adhesive or the like. In the present embodiment, the second transparent film 33c is a (meth) acrylic resin-based film, but is not limited to this, and may be a TAC-based film like the first transparent film 33b. In this case, it is preferable that the second transparent film 33c also does not contain a phosphoric acid-based plasticizer.

The thickness of the first transparent film 33b and the second transparent film 33c should be thicker than that of the polarizer 33a, but the thickness is not limited to this, and the thickness of the first transparent film 33b and the second transparent film 33c is not limited to this. It may be thinner than the polarizer 33a.

The third polarizing plate 33 configured in this way has a smaller amount of water than the first polarizing plate 31 and the second polarizing plate 32. That is, the amount of water contained in the third polarizing plate 33 is smaller than the amount of water contained in the first polarizing plate 31, and is smaller than the amount of water contained in the second polarizing plate 32. Specifically, the amount of water per unit area of the third polarizing plate 33 is 6 g / m ² or less. As an example, the water content per unit area of the third polarizing plate 33 is about 5.3 g / m ² , and the water content of the first polarizing plate 31 and the second polarizing plate 32 per unit area is about 6. It is 3 g / m ² .

Further, the first transparent film 33b and the second transparent film 33c in the third polarizing plate 33 should have high moisture permeability (moisture transmittance). As a result, the water content in the polarizer 33a easily permeates through the first transparent film 33b and the second transparent film 33c and is easily diffused to the outside of the third polarizing plate 33. Therefore, the third polarizing plate by polyeneizing PVA, which will be described later. The decrease in the transmittance of 33 tends to be suppressed.

Further, the fourth polarizing plate 34 includes a polarizing element and a transparent protective film that protects both sides of the polarizing element, similarly to the third polarizing plate 33. Specifically, the fourth polarizing plate 34 is laminated on the polarizer 34a, the first transparent film 34b which is a transparent protective film laminated on one surface of the polarizer 34a, and the other surface of the polarizer 34a. It has a second transparent film 34c, which is a transparent protective film. That is, the polarizer 34a is sandwiched between the first transparent film 33b and the second transparent film 33c.

In the present embodiment, the fourth polarizing plate 34 is the same as the third polarizing plate 33. Specifically, the fourth polarizing plate 34 and the third polarizing plate 33 are the same products. Therefore, the material and thickness of the polarizer 34a are the same as the material and thickness of the polarizer 33a. Further, the material and thickness of the first transparent film 34b are the same as the material and thickness of the first transparent film 33b, and the material and thickness of the second transparent film 34c are also the material and thickness of the second transparent film 33c. And so on. The amount of water contained in the fourth polarizing plate 34 is also the same as that of the third polarizing plate 33, which is about 5.3 g / m ² .

The fourth polarizing plate 34 is arranged so that the first transparent film 33b of the first transparent film 34b and the second transparent film 34c is located on the bonding member 500 side. Therefore, in the fourth polarizing plate 34, the first transparent film 34b, which is a TAC-based film that does not contain a phosphoric acid-based plasticizer, is bonded to the surface of the polarizer 34a on the bonding member 500 side, and is (meth) acrylic. The second transparent film 34c, which is a resin-based film, is bonded to the surface of the polarizer 34a opposite to the bonding member 500 side (the surface on the second liquid crystal cell 20 side).

The first polarizing plate 31 and the second polarizing plate 32 are different from the third polarizing plate 33 in that the transparent protective film is laminated on both sides of the polarizing element, similarly to the third polarizing plate 33. Is. Specifically, the first polarizing plate 31 and the second polarizing plate 32 are the same as the third polarizing plate 33 and the fourth polarizing plate 34 in that the polarizer is a PVA-based film containing iodine, but polarized light. It differs from the third polarizing plate 33 and the fourth polarizing plate 34 in that the two transparent protective films sandwiching the child are both TAC films.

The first display panel 100 in which the first polarizing plate 31 and the third polarizing plate 33 are bonded to the first liquid crystal cell 10, and the second polarizing plate 34 to which the fourth polarizing plate 34 and the second polarizing plate 32 are bonded to the second liquid crystal cell 20. The two display panels 200 are joined via a joining member 500. Specifically, the first display panel 100 and the second display panel 200 are bonded to each other by a joining member 500.

In the present embodiment, the joining member 500 is arranged between the third polarizing plate 33 of the first display panel 100 and the fourth polarizing plate 34 of the second display panel 200, and the third polarizing plate 33 and the third polarizing plate 34 are arranged. 4 It is joined to the polarizing plate 34.

The joining member 500 is an adhesive such as a film-shaped optical transparent adhesive sheet (OCA), and is made of a resin material such as an acrylic material. The joining member 500 may be composed of a plurality of laminated adhesive resin sheets.

Further, the thickness of the joining member 500 is preferably equal to or larger than the thickness of the polarizer 33a of the third polarizing plate 33. In the present embodiment, the thickness of the joining member 500 is thicker than the total thickness of the third polarizing plate 33.

Next, the operation and effect of the liquid crystal display device 1 according to the present embodiment will be described together with the background to the present disclosure.

The display panel used in the liquid crystal display device has a liquid crystal cell and a pair of polarizing plates sandwiching the liquid crystal cell. Conventionally, an image display device having a high contrast ratio has been studied by superimposing a plurality of such display panels and bonding them with a joining member such as OCA.

However, when a liquid crystal display device in which a plurality of display panels are bonded by a joining member is used for a long time, the display screen may be colored. In particular, the central part of the display screen may be colored as if it is brownish. When the display screen is colored in this way, the quality of the displayed image deteriorates.

When the present inventors investigated the cause of such coloring of the display screen, it was found that the polarizing plate attached to the liquid crystal cell was discolored. In particular, in a liquid crystal display device in which two display panels are overlapped, three or four polarizing plates are used, and the polarizing plate arranged between two liquid crystal cells among these polarizing plates discolors. It turned out. In particular, it was found that the in-plane central portion of the polarizing plate turned brown.

As a result of diligent studies on the cause of such discoloration of the polarizing plate, the present inventors have found that the polarizing plate is discolored due to the material of the polarizing plate and the moisture contained in the polarizing plate. This point will be described below.

The polarizing plate has a polarizing element and a transparent protective film laminated on the polarizing element. As the material of the polarizer, for example, a PVA-based film containing iodine is used.

When PVA of PVA-based film is heated, it is dehydrated and polyenes. That is, a polyene structure (-(C = C) _n- ) is formed in PVA, and PVA is denatured. In this way, when PVA is polyene, the polarizing plate is discolored and absorbs visible light.

Further, as a material for the transparent protective film of the polarizing plate, for example, a TAC film is used. In this case, a phosphoric acid-based plasticizer may be contained in order to give the TAC-based film a function such as flexibility.

Here, when a TAC film containing a phosphoric acid-based plasticizer is exposed to a high-temperature and high-humidity environment for a long time, the TAC-based film is hydrolyzed by acid impurities contained in the phosphoric acid-based plasticizer to form an acid. Is generated. Specifically, when the TAC film is hydrolyzed, acetic acid is produced.

At this time, if water is contained in the polarizing plate, the hydrolysis of the TAC film by the acid impurities of the phosphoric acid-based plasticizer is promoted, and a large amount of acetic acid is present in the polarizing plate. ..

Here, the polyene formation of PVA is mainly due to the dehydration reaction, but is promoted by the presence of acid. That is, the acid acts as a catalyst to promote the dehydration reaction of PVA.

Therefore, as described above, when the TAC film is hydrolyzed by the acid impurities of the phosphoric acid-based plastic agent to generate an acid (acetic acid), this acid acts as a catalyst to promote the dehydration reaction of PVA, and PVA Will progress to polyenization.

Moreover, once PVA is polyenylated, water is generated by the dehydration reaction of PVA, the amount of water in the polarizing plate is increased, the TAC film is easily hydrolyzed, and acetic acid is more likely to be generated. As a result, the polyene formation of PVA progresses at an accelerating rate.

Therefore, when the polarizing plate in the liquid crystal display device is heated by, for example, a backlight, the PVA of the PVA-based film constituting the polarizing element of the polarizing plate undergoes a dehydration reaction, and is included in the polarizing plate at this time. The acetic acid produced by hydrolyzing the TAC-based film constituting the transparent protective film of the polarizing plate with water serves as a catalyst to promote the dehydration reaction. As a result, polyeneization of PVA progresses and the polarizing plate is discolored.

In particular, the main surface of the polarizing plate located between the two liquid crystal cells is in close contact with the joining member and sealed. For this reason, it is considered that some water is released from the end portion at the peripheral portion of the polarizing plate, but it is difficult for the moisture to escape at the in-plane central portion of the polarizing plate. As a result, since more water is present in the in-plane central portion of the polarizing plate than in the peripheral portion of the polarizing plate, hydrolysis of the TAC film is promoted and a large amount of acetic acid is likely to be generated. Further, since the in-plane central portion of the polarizing plate tends to have a higher temperature than the peripheral portion of the polarizing plate, polyene formation of PVA tends to proceed.

Therefore, in the in-plane central portion of the polarizing plate, the reaction promotion by acetic acid (catalyst) generated by the hydrolysis of the TAC film and the reaction promotion by the high temperature of the polarizing plate are combined to further promote the dehydration reaction of PVA. , PVA polyenization will proceed at an accelerating rate. On the contrary, since the temperature of the reaction system does not easily rise in the peripheral portion of the polarizing plate, the dehydration reaction of PVA does not proceed easily. As a result, in the polarizing plate arranged between the two liquid crystal cells, the in-plane central portion turns brown.

As described above, when the present inventors construct a liquid crystal display device by joining display panels in which a polarizing plate is attached to a liquid crystal cell with a joining member, the polarizer is a PVA-based film and a transparent protective film. It was found that when a polarizing plate, which is a TAC-based film containing a phosphoric acid-based plasticizing agent, was used, the polarizing plate was discolored.

The present disclosure has been made based on such findings, and the present inventors have obtained that, for a polarizing plate arranged between two liquid crystal cells, the material and polarization of the polarizer and the transparent protective film in the polarizing plate. It has been found that discoloration of the polarizing plate can be suppressed by defining the amount of water contained in the plate.

Specifically, in the liquid crystal display device 1 of the present embodiment, the PVA-based film containing iodine as the polarizer 33a of the third polarizing plate 33 arranged between the first liquid crystal cell 10 and the bonding member 500. As the first transparent film 33b, a TAC-based film that does not contain a phosphoric acid-based plasticizer is used, and the water content per unit area of the third polarizing plate 33 is 6 g / m ² or less. ..

In this way, the amount of water per unit area of the third polarizing plate 33 is reduced to a small amount of 6 g / m ² or less, and the TAC-based film of the first transparent film 33b does not contain a phosphoric acid-based plasticizer. Hydrolysis of the system film can be suppressed. As a result, it is possible to suppress the formation of acetic acid, which is a catalyst for the dehydration reaction of PVA, due to the hydrolysis of the TAC film, so that the dehydration reaction of PVA can be suppressed. As a result, the polyene formation of PVA can be suppressed, so that the discoloration of the third polarizing plate 33 can be suppressed.

Moreover, the third polarizing plate 33 configured in this way is more weather resistant than the first polarizing plate 31 and the second polarizing plate 32 in which the two transparent protective films on both sides of the polarizer are both made of a TAC film. It also has excellent properties and heat resistance. Therefore, by using the third polarizing plate 33 as the polarizing plate arranged between the first liquid crystal cell 10 and the second liquid crystal cell 20, a highly reliable liquid crystal display device having excellent weather resistance and heat resistance is realized. be able to.

Further, in the liquid crystal display device 1 according to the present embodiment, the first display panel 100 and the second display panel 200 are joined by a joining member 500, and the third polarizing plate 33 of the first display panel 100 is joined. It is in close contact with the member 500.

As the joining member 500, for example, an OCA such as an acrylic resin is used, but when the OCA is exposed to a high temperature environment, the OCA vaporizes to generate an acid. For example, when OCA is composed of acrylic resin, OCA is vaporized to generate acrylic acid.

In this case, when the acid generated by the vaporization of the bonding member 500 moves to the polarizer 33a of the third polarizing plate 33, not only the acid generated by the hydrolysis of the TAC film but also the acid generated by the vaporization of the bonding member 500. Also acts as a catalyst and may promote the dehydration reaction of PVA constituting the polarizer 33a.

However, in the liquid crystal display device 1 according to the present embodiment, the amount of water per unit area of the third polarizing plate 33 is reduced to a small amount of 6 g / m ² or less, and the third polarizing plate 33 is provided on the bonding member 500 side of the polarizer 33a. Since the TAC-based film constituting the first transparent film 33b does not contain a phosphoric acid-based plasticizer, it is possible to suppress the generation of acetic acid due to the hydrolysis of the TAC-based film, and it is possible to suppress the polyene formation of PVA.

As described above, according to the liquid crystal display device 1 according to the present embodiment, discoloration of the third polarizing plate 33 arranged between the first liquid crystal cell 10 and the joining member 500 can be suppressed. As a result, it is possible to suppress the occurrence of coloring on the display screen and the deterioration of the quality of the displayed image.

Here, the present inventors have conducted an experiment on the relationship between the material and water content of the polarizing plate and the discoloration of the polarizing plate, which will be described below.

In this experiment, two substrates with polarizing plates attached to a 200 μm square glass plate were prepared, and these two substrates were arranged so that the polarizing plates faced each other and bonded by OCA, which was used as a sample. Each of the polarizing plates used in this experiment has a polarizer made of PVA and a transparent film bonded to both sides of the polarizer. Moreover, in this experiment, four kinds of samples A to D were prepared. The samples A to D have the same glass plate, and the material of the transparent film of the polarizing plate, the amount of water contained in the polarizing plate, and the OCA are mainly changed.

Specifically, in Samples A and B, the thickness of the polarizer was 28 μm, the water content per unit area of the polarizing plate was 6.3 g / m ² , and triphenyl phosphate (TPP) as a phosphoric acid-based plasticizer. A polarizing plate made of a transparent film containing () was used, and as the OCA, an acrylic-based one having a thickness of 600 μm was used for sample A, and an acrylic-based one having a thickness of 1000 μm was used for sample B. The samples A and B correspond to the first polarizing plate 31.

On the other hand, in the samples C and D, the thickness of the polarizer was 28 μm, the amount of water per unit area of the polarizing plate was 5.3 g / m ² , and the phosphoric acid-based plasticizer provided on the OCA side of the polarizer was used. A polarizing plate containing a transparent film containing no transparent film and a transparent film made of a (meth) acrylic resin-based film provided on the glass plate side of the polarizer is used, and as OCA, acrylic having a thickness of 600 μm in sample C is used. An acrylic film having a thickness of 1000 μm was used for sample D. The samples C and D correspond to the third polarizing plate 33.

Then, in this experiment, the durability was confirmed by leaving the samples A to D for 2500 hours in an environment where the temperature was 80 ° C. and the humidity was 3%, and the color change of each sample was confirmed. Specifically, those having a large change in color were evaluated as having no durability, and those having a small change in color were evaluated as having durability. The results are shown in Table 1 below.

As shown in Table 1, it can be seen that the samples C and D have less color change after a long period of time and are excellent in durability as compared with the samples A and B.

Furthermore, from the results of this experiment, the present inventors can suppress the brown color of the third polarizing plate 33 as the thickness of the joining member 500 that joins the first display panel 100 and the second display panel 200 is increased. I thought that it might be, and conducted an experiment on this as well. The results of this experiment will be described below.

In this experiment, the same sample A and sample B as above were used. Then, the samples A and B were left to stand in an environment where the temperature was 80 ° C. and the humidity was 3%, and the chromaticity of each of the samples A and B was measured over time with a surface chromaticity meter. At this time, the difference in chromaticity between the peripheral portion and the central portion of each sample (chromaticity of the peripheral portion-chromaticity of the central portion) is set as the V'value, and this V'value is used to make the "brown" of the samples A and B. Degree "was evaluated.

The results of this experiment are shown in FIG. FIG. 3 is a diagram showing the change over time in the brownness of the two polarizing plates bonded by OCA. In FIG. 3, the vertical axis indicates the ratio of V'values, and the lower the value on the vertical axis, the higher the degree of browning in the central portion of the sample. In other words, the lower the value on the vertical axis, the more brown the color. Further, in FIG. 3, the horizontal axis represents time (h).

In FIG. 3, the broken line shows the chromaticity of sample A (OCA 600 μm thickness) with time, and the solid line shows the chromaticity of sample B (OCA 1000 μm thickness) with time.

As shown in FIG. 3, it can be seen that the sample B is less likely to be browned than the sample A. In particular, in sample A, the degree of browning tends to increase and browning tends to be conspicuous from around 1000 hours, but in sample B, the degree of browning is slow even after 1000 hours, and most of the time. It can be seen that it does not turn brown. As described above, it can be seen that when the thickness of OCA is increased, it tends to be difficult to brown, and conversely, when the thickness of OCA is decreased, it tends to be browned easily.

From this experimental result, it was found that the thicker the joining member 500 that joins the first display panel 100 and the second display panel 200, the more the third polarizing plate 33 can be suppressed from turning brown.

One factor that can suppress the browning of the third polarizing plate 33 by increasing the thickness of the bonding member 500 in this way is that the moisture contained in the third polarizing plate 33 can be removed by increasing the thickness of the bonding member 500. It is considered that this is because the amount that can be absorbed by the joining member 500 (water absorption capacity) has increased. That is, it is considered that the amount of water contained in the third polarizing plate 33 can be reduced by increasing the thickness of the joining member 500. By reducing the amount of water contained in the third polarizing plate 33 in this way, it is possible to effectively suppress the generation of acid due to the hydrolysis of the TAC-based film constituting the first transparent film 33b. As a result, the polyene formation of PVA constituting the polarizer 33a can be suppressed, and the discoloration of the third polarizing plate 33 to brown can be suppressed.

Therefore, in the liquid crystal display device 1 according to the present embodiment, in order to increase the thickness of the bonding member 500, the thickness of the bonding member 500 is set to be equal to or larger than the thickness of the polarizing element 33a of the third polarizing plate 33.

As a result, the first display panel 100 and the second display panel 200 are joined by the joining member 500, and the third polarizing plate 33 is arranged between the first liquid crystal cell 10 and the joining member 500. Also, it is possible to effectively suppress the discoloration of the third polarizing plate 33. Therefore, it is possible to further suppress the deterioration of the quality of the displayed image.

The thickness of the joining member 500 should be thicker than the total thickness of the third polarizing plate 33. Further, in the present embodiment, the thickness of the joining member 500 is thicker than the thickness of the fourth polarizing plate 34, and further thicker than the thickness of the first polarizing plate 31 and the second polarizing plate 32. ..

Further, in the liquid crystal display device 1 according to the present embodiment, the second transparent film 33c of the third polarizing plate 33 is a (meth) acrylic resin-based film.

With this configuration, the oblique viewing angle can be improved. Thereby, the quality of the displayed image can be improved.

Further, in the liquid crystal display device 1 of the present embodiment, the fourth polarizing plate 34 is arranged between the second liquid crystal cell 20 and the joining member 500. The fourth polarizing plate 34 is the same as the third polarizing plate 33.

As a result, it is possible to suppress the formation of acetic acid, which is a catalyst for the dehydration reaction of PVA, due to the hydrolysis of the TAC film in the fourth polarizing plate 34 as well. As a result, it is possible to suppress the dehydration reaction of PVA of the fourth polarizing plate 34 as well, and it is possible to suppress the polyene formation of PVA. As a result, discoloration of the fourth polarizing plate 34 can be suppressed. Therefore, it is possible to further suppress the deterioration of the quality of the displayed image.

(Modification example)
The liquid crystal display device according to the present disclosure has been described above based on the embodiment, but the present disclosure is not limited to the above embodiment.

For example, the first diffusion layer 41 may be arranged between the third polarizing plate 33 and the bonding member 500, as in the liquid crystal display device 2 according to the modification shown in FIG. The first diffusion layer 41 is a diffusion film (diffusion plate) having a light diffusion function. The first diffusion layer 41 may have a structure in which the light diffusing material is dispersed (internal haze structure), or may have a surface uneven structure (external haze structure) formed by subjecting an antiglare treatment or the like. It may have both an internal haze structure and an external haze structure.

By arranging the first diffusion layer 41 in this way, it is possible to suppress the occurrence of moire due to the pattern shape of the black matrix of the second liquid crystal cell 20 and the like. The first diffusion layer 41 is attached to the third polarizing plate 33 with, for example, an adhesive or the like. The first diffusion layer 41 may be an optical film integrated with the third polarizing plate 33.

Further, in the liquid crystal display device 2 shown in FIG. 4, a second diffusion layer 42 is also arranged between the fourth polarizing plate 34 and the bonding member 500. As the second diffusion layer 42, a layer having the same structure as that of the first diffusion layer 41 can be used.

By arranging the second diffusion layer 42 in this way, the occurrence of moire can be further suppressed. The second diffusion layer 42 is attached to the fourth polarizing plate 34 with, for example, an adhesive or the like. The second diffusion layer 42 may also be an optical film integrated with the fourth polarizing plate 34.

Further, in the above-described embodiment and modification, the first polarizing plate 31, the second polarizing plate 32, the third polarizing plate 33, and the fourth polarizing plate 34 have other functions such as a retardation plate (phase difference film). The films may be bonded together. These functional films may be an optical film integrated with each of the first polarizing plate 31, the second polarizing plate 32, the third polarizing plate 33, and the fourth polarizing plate 34, or may be a separate body. ..

Further, in the above-described embodiment and modification, the first polarizing plate 31, the second polarizing plate 32, the third polarizing plate 33, and the fourth polarizing plate 34 are 3 of a pair of transparent protective films sandwiching a polarizing element and a polarizing element. It has a layered structure, but it is not limited to this. The first polarizing plate 31, the second polarizing plate 32, the third polarizing plate 33, and the fourth polarizing plate 34 have a resin base material layer, an adhesive layer, or the like in addition to the polarizing element and the pair of transparent protective films. May be good. In this case, the resin base material layer or the adhesive layer may be provided on the outer surface of the transparent protective film, but may be inserted between the polarizer and the transparent protective film. That is, the first polarizing plate 31, the second polarizing plate 32, the third polarizing plate 33, and the fourth polarizing plate 34 are not those in which three resin films of a polarizer and a pair of transparent protective films are continuously laminated. You may.

Further, in the above-described embodiment and modification, the second polarizing plate 32 may be the same as the third polarizing plate 33. Since the second polarizing plate 32 is arranged at the position closest to the backlight 300 among the four polarizing plates, it is exposed to the highest temperature among the four polarizing plates. Therefore, by using the same second polarizing plate 32 as the third polarizing plate 33, which is excellent in weather resistance and heat resistance, deterioration of the second polarizing plate 32 due to heat can be suppressed. As a result, a more reliable liquid crystal display device can be realized.

Further, in the above-described embodiment and modified example, two polarizing plates, a third polarizing plate 33 and a fourth polarizing plate 34, are inserted between the first liquid crystal cell 10 and the second liquid crystal cell 20. However, only one of the third polarizing plate 33 and the fourth polarizing plate 34 may be arranged between the first liquid crystal cell 10 and the second liquid crystal cell 20. When the third polarizing plate 33 is not arranged and is composed of only the first polarizing plate 31, the second polarizing plate 32, and the fourth polarizing plate 34, the fourth polarizing plate 34 is referred to as the third polarizing plate. Become.

Further, in the above-described embodiment and modification, two display panels are used, but the present invention is not limited to this. For example, three or more display panels may be used.

In addition, various modifications that can be considered by those skilled in the art are applied to the above-described embodiments and modifications, and the components and functions of the embodiments and modifications are arbitrarily combined without departing from the spirit of the present disclosure. The form realized by this is also included in the present disclosure.

1, 2 Liquid crystal display device 10 1st liquid crystal cell 11 1st TFT substrate 12 1st opposed substrate 13 1st liquid crystal layer 20 2nd liquid crystal cell 21 2nd TFT substrate 22 2nd opposed substrate 23 2nd liquid crystal layer 31 1st polarizing plate 32 2nd polarizing plate 33 3rd polarizing plate 33a, 34a Polarizers 33b, 34b 1st transparent film 33c, 34c 2nd transparent film 34 4th polarizing plate 41 1st diffusion layer 42 2nd diffusion layer 100 1st display panel 101 1 Image display area 102 1st source driver 103 1st gate driver 200 2nd display panel 201 2nd image display area 202 2nd source driver 203 2nd gate driver 300 Backlight 410 1st timing controller 420 2nd timing controller 430 image Processing unit 500 Joining member

Claims (7)

The first display panel including the first liquid crystal cell and
A second display panel, which is arranged so as to overlap the first display panel and includes a second liquid crystal cell,
A joining member arranged between the first display panel and the second display panel and joining the first display panel and the second display panel,
A first polarizing plate provided on a surface of the first liquid crystal cell opposite to the surface on the bonding member side,
A second polarizing plate provided on a surface of the second liquid crystal cell opposite to the surface on the bonding member side,
A third polarizing plate arranged between the first liquid crystal cell and the joining member and between the second liquid crystal cell and the joining member is provided.
The third polarizing plate has a polarizer and a first transparent film provided on the bonding member side of the polarizer.
The polarizer is a polyvinyl alcohol-based film containing iodine.
The thickness of the polarizer is 26 μm or more and 30 μm or less.
The first transparent film is a triacetyl cellulose-based film that does not contain a phosphoric acid-based plasticizer.
The amount of water per unit area of the third polarizing plate is 6 g / m ² or less.
Liquid crystal display device. The thickness of the joining member is equal to or greater than the thickness of the third polarizing plate.
The liquid crystal display device according to claim 1. The third polarizing plate further has a second transparent film provided on the side of the polarizer opposite to the bonding member side.
The second transparent film is a (meth) acrylic resin-based film.
The liquid crystal display device according to claim 1 or 2. A diffusion layer is arranged between the third polarizing plate and the bonding member.
The liquid crystal display device according to any one of claims 1 to 3. A fourth polarizing plate arranged between the first liquid crystal cell and the joining member and between the second liquid crystal cell and the joining member is provided.
The fourth polarizing plate is the same as the third polarizing plate.
The liquid crystal display device according to any one of claims 1 to 4. The second polarizing plate is the same as the third polarizing plate.
The liquid crystal display device according to any one of claims 1 to 5. Further equipped with a backlight arranged to face the second display panel,
The second display panel is arranged between the first display panel and the backlight.
The liquid crystal display device according to any one of claims 1 to 6.

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