JP5222477B2 - Display device - Google Patents

Description

The present invention relates to a configuration of a display device having a polarizer.

Development is progressing on so-called flat panel displays, which are very thin and light in weight compared to conventional CRT displays. Flat panel displays are competing with liquid crystal display devices with liquid crystal elements as display elements, light emitting devices with self-luminous elements, FED (field emission display) using electron beams, etc. Therefore, low power consumption and high contrast ratio are demanded.

In general, a liquid crystal display device is provided with one polarizing plate on each substrate, and maintains a contrast ratio. By making the black display darker, the contrast ratio can be increased, and a high display quality can be provided when an image is viewed in a dark room like a home theater.

For example, in order to improve display non-uniformity and contrast ratio caused by insufficient polarization degree and polarization degree distribution of the polarizing plate, a first polarizing plate is provided outside the substrate on the viewing side of the liquid crystal cell, When a second polarizing plate is provided outside the opposite substrate and the light from the auxiliary light source provided on the opposite substrate side is polarized through the second polarizing plate and passes through the liquid crystal cell, the degree of polarization In order to improve the above, a configuration in which a third polarizing plate is provided has been proposed (see Patent Document 1).
International Publication No. 00/34821

However, the demand for increasing the contrast ratio is not limited, and further improvement in the contrast ratio is demanded and studied in liquid crystal display devices. In addition, there is a problem that a polarizing plate having a high degree of polarization is expensive.

Although the method of improving the contrast ratio by using three polarizing plates as in Patent Document 1 is a method that can be realized by using an inexpensive polarizing plate, it is difficult to realize a higher level contrast ratio. In addition, the wavelength dependence of the absorption characteristics of the polarizing plate is not constant, and the absorption characteristics in a specific wavelength region are lower than those in other wavelength regions, i.e., it is difficult to absorb only that wavelength region. Yes. Therefore, even if an attempt is made to improve the contrast ratio using a plurality of polarizing plates of the same type, a wavelength region that hardly absorbs light exists as it is. Therefore, this causes a slight light leakage, and this light leakage hinders further improvement of the contrast ratio.

In view of the above problems, an object of the present invention is to provide a display device having a high contrast ratio by a simple method. Another object is to produce such a high-performance display device at low cost.

In the present invention, a layer including a laminated polarizer is provided on at least one of the light-transmitting substrates arranged so as to face each other, and the laminated polarizers have different extinction coefficients and have absorption axes. It is arranged so as to deviate from parallel Nicols. Further, a wave plate or a retardation plate may be provided between the laminated polarizer and the substrate.

A polarizer has an absorption axis, and when laminating polarizers, the case where the absorption axes of the polarizers are parallel is called parallel Nicol, and the case where the absorption axes of the polarizers are orthogonal is crossed. Call it Nicole. Note that due to the characteristics of the polarizer, there is a transmission axis in a direction orthogonal to the absorption axis. Therefore, the case where the transmission axes are parallel to each other can also be referred to as parallel Nicol, and the case where the transmission axes are in an orthogonal state can also be referred to as crossed Nicol.

Further, the polarizer has an intrinsic extinction coefficient with respect to light. This is because the wavelength dependence of the absorption characteristic of the polarizer is not constant, and the absorption characteristic in a specific wavelength region is lower than the absorption characteristic in other wavelength regions, that is, it has a characteristic that it is difficult to absorb only that wavelength region. It depends on In the present invention, the extinction coefficients of the absorption axes of the stacked polarizers are different, that is, the distributions of the extinction coefficients of the absorption axes with respect to the wavelengths are different between the stacked polarizers.

By using the present invention and laminating and combining polarizers having different extinction coefficients with respect to the absorption axis, it is possible to eliminate or reduce the wavelength region in which light is difficult to absorb. Therefore, slight light leakage can be prevented and the contrast ratio can be further improved.

One embodiment of a display device of the present invention is provided between a first light-transmitting substrate and a second light-transmitting substrate which are arranged to face each other, and between the first light-transmitting substrate and the second light-transmitting substrate. The sandwiched display element has a layer including a stacked polarizer on the outside of the first light-transmitting substrate or the second light-transmitting substrate, and the stacked polarizers have an absorption axis. The laminated polarizers are arranged such that their absorption axes deviate from parallel Nicols.

One embodiment of a display device of the present invention is provided between a first light-transmitting substrate and a second light-transmitting substrate which are arranged to face each other, and between the first light-transmitting substrate and the second light-transmitting substrate. The sandwiched display element, the first light-transmitting substrate, or the second light-transmitting substrate on the outer side, a layer including a stacked polarizer, the first light-transmitting substrate, or the second light-transmitting substrate. A retardation plate is provided between the optical substrate and the layer including the laminated polarizer, and the laminated polarizers have mutually different extinction coefficients with respect to the absorption axis, and the laminated polarizers absorb each other. The shaft is arranged so as to deviate from parallel Nicols.

One embodiment of a display device of the present invention is provided between a first light-transmitting substrate and a second light-transmitting substrate which are arranged to face each other, and between the first light-transmitting substrate and the second light-transmitting substrate. A sandwiched display element, a first layer including a first laminated polarizer on the outside of the first light-transmitting substrate, and a second layer on the outside of the second light-transmitting substrate. The first laminated polarizers have different extinction coefficients with respect to the absorption axis, and the second laminated polarizers have extinction with respect to the absorption axis. The first stacked polarizers are arranged such that their absorption axes deviate from parallel Nicols, and the second stacked polarizers are arranged so that their absorption axes are parallel Nicols. Is done.

One embodiment of a display device of the present invention is provided between a first light-transmitting substrate and a second light-transmitting substrate which are arranged to face each other, and between the first light-transmitting substrate and the second light-transmitting substrate. A sandwiched display element, a first layer including a first laminated polarizer on the outside of the first light-transmitting substrate, and a second layer on the outside of the second light-transmitting substrate. A first retardation plate, a first light transmitting substrate, a first light transmitting substrate, and a first light transmitting substrate between the first light transmitting substrate and the layer including the first stacked polarizer. A second retardation plate between the layers including the two stacked polarizers, and the first stacked polarizers have different extinction coefficients with respect to the absorption axis, and the second stacked The polarizers have mutually different extinction coefficients with respect to the absorption axis, and the first stacked polarizers are arranged such that their absorption axes deviate from parallel Nicols, and the second stacked polarized light It is arranged so that their absorption axes are in a parallel nicol state.

One embodiment of a display device of the present invention is provided between a first light-transmitting substrate and a second light-transmitting substrate which are arranged to face each other, and between the first light-transmitting substrate and the second light-transmitting substrate. A sandwiched display element, a first layer including a first laminated polarizer on the outside of the first light-transmitting substrate, and a second layer on the outside of the second light-transmitting substrate. The first laminated polarizers have different extinction coefficients with respect to the absorption axis, and the second laminated polarizers have extinction with respect to the absorption axis. The first stacked polarizers are arranged such that their absorption axes deviate from parallel Nicols, and the second stacked polarizers are arranged so that their absorption axes are parallel Nicols. The first laminated polarizer-containing layer is laminated in the order of the first polarizer and the second polarizer from the first translucent substrate side. Is, first polarizer and the second stacked polarizers are arranged so that their absorption axes are in a cross nicol state.

One embodiment of a display device of the present invention is provided between a first light-transmitting substrate and a second light-transmitting substrate which are arranged to face each other, and between the first light-transmitting substrate and the second light-transmitting substrate. A sandwiched display element, a first layer including a first laminated polarizer on the outside of the first light-transmitting substrate, and a second layer on the outside of the second light-transmitting substrate. A second retardation layer including the first polarizer, a first retardation plate between the first transparent substrate and the first layer including the first stacked polarizer, and a second transparency. A second retardation plate between the substrate and the second layer including the second laminated polarizer, the first laminated polarizers have different extinction coefficients with respect to the absorption axis, The second stacked polarizers have mutually different extinction coefficients with respect to the absorption axis, and the first stacked polarizers are arranged such that their absorption axes deviate from parallel Nicols, and the second product The polarizers are arranged so that their absorption axes are parallel Nicols, and the layer including the first stacked polarizers includes the first polarizer and the second polarizer from the first translucent substrate side. The first polarizer and the second stacked polarizer are arranged so that their absorption axes are crossed Nicols.

In the display device of the present invention, when a light source serving as a backlight is used, light is allowed to pass through a display element from a layer including a stacked polarizer on the side opposite to the viewing side, and is extracted from the layer including a polarizer on the viewing side. It is preferable that the absorption axes of the laminated polarizers on the side opposite to the viewing side (backlight side) are parallel Nicols because the transmittance of light from the backlight is increased.

In the display device of the present invention, in the layer including the stacked polarizers, a structure in which a stack of a plurality of polarizers is provided between a pair of protective layers, and each polarizer is sandwiched between a pair of protective layers. The structure provided in may be sufficient. The laminated layer including the polarizer may have a structure in which an antireflection film or an antiglare film is provided on the viewing side.

Light leakage can be reduced and the contrast ratio of the display device can be further increased by a simple structure in which a plurality of polarizers having different absorption coefficients of absorption axes are provided by laminating the absorption axes. In addition, such a high-performance display device can be manufactured at low cost.

Embodiments of the present invention will be described below with reference to the drawings. However, the present invention can be implemented in many different modes, and those skilled in the art can easily understand that the modes and details can be variously changed without departing from the spirit and scope of the present invention. Is done. Therefore, the present invention is not construed as being limited to the description of this embodiment mode. Note that in all the drawings for describing the embodiments, the same portions or portions having similar functions are denoted by the same reference numerals, and repetitive description thereof is omitted.

(Embodiment 1)
In this embodiment mode, a concept of a display device provided with a layer including a pair of stacked polarizers using the present invention will be described.

In FIG. 1A, a pair of layers including polarizers having different extinction coefficients of absorption axes from each other is included, and at least one of the layers including the stacked polarizers is shifted from parallel Nicols. FIG. 1B is a perspective view of a display device having the above structure. In this embodiment, a liquid crystal display device including a liquid crystal element as a display element is described as an example.

As shown in FIG. 1A, a layer 100 having a liquid crystal element is sandwiched between a first substrate 101 and a second substrate 102 which are arranged to face each other.

In this embodiment mode, a layer including a stacked polarizer is provided on the outside of the substrate, that is, the side not in contact with the layer having a liquid crystal element. Specifically, as illustrated in FIG. 1A, a layer 103 including a first polarizer and a layer 104 including a second polarizer are provided on the first substrate 101 side. Further, a layer 105 including a third polarizer and a layer 106 including a fourth polarizer are provided on the second substrate 102 side. In this embodiment mode, a layer including stacked polarizers having different extinction coefficients of a pair of absorption axes is characterized in that at least one layer including stacked polarizers is shifted from parallel Nicols. Specifically, as shown in FIG. 1B, the absorption axis (A) of the layer 103 including the first polarizer having a different extinction coefficient of the absorption axis and the layer 104 including the second polarizer The absorption axes (B) are shifted from the parallel state and stacked. Then, the absorption axis (C) of the layer 105 including the third polarizer having a different extinction coefficient of the absorption axis and the absorption axis (D) of the layer 106 including the fourth polarizer are parallel to each other. In other words, the layers are laminated so as to be parallel Nicols.

The wavelength dependency of the absorption characteristics of the polarizer is not constant, and the absorption characteristics in a specific wavelength region are lower than the absorption properties in other wavelength regions, that is, the polarizer has a property that it is difficult to absorb only that wavelength region. Therefore, even if an attempt is made to improve the contrast ratio using a plurality of polarizers of the same type, a wavelength region that hardly absorbs light exists as it is. Therefore, by using the present invention and laminating and combining polarizers having different extinction coefficients with respect to the absorption axis, it is possible to eliminate or reduce the wavelength region where it is difficult to absorb light. Therefore, slight light leakage can be prevented and the contrast ratio can be further improved.

The substrate is an insulating substrate having a light-transmitting property (hereinafter also referred to as a light-transmitting substrate). In particular, it has translucency in the wavelength region of visible light. For example, a glass substrate such as barium borosilicate glass or alumino borosilicate glass, a quartz substrate, or the like can be used. In addition, a substrate made of a plastic such as polyethylene-terephthalate (PET), polyethylene naphthalate (PEN), or polyethersulfone (PES), or a synthetic resin having flexibility such as acrylic can be used. In addition, a film (made of polypropylene, polyester, vinyl, polyvinyl fluoride, vinyl chloride, or the like), a base film (polyester, polyamide, inorganic vapor deposition film, or the like) can also be used.

Although not illustrated in FIG. 1, irradiation means such as a backlight is disposed below the layer 106 including the fourth polarizer.

Note that in this embodiment, the layer 103 including the first polarizer and the layer 105 including the third polarizer are arranged so as to be crossed Nicols. As long as a predetermined black display is obtained, the layer 103 including the first polarizer and the layer 105 including the third polarizer may be deviated from the crossed Nicols state.

FIG. 5 shows the absorption axis (A) of the layer 103 including the first polarizer, the absorption axis (B) of the layer 104 including the second polarizer, and the absorption of the layer 105 including the third polarizer. The figure which looked at the angle | corner which the axis | shaft (C) and the absorption axis (D) of the layer 106 containing a 4th polarizer look from the upper surface is shown. The absorption axis (A) of the layer 103 including the first polarizer and the absorption axis (B) of the layer 104 including the second polarizer are stacked with a shift angle θ. In the present embodiment, the absorption axis (C) and the absorption axis (D) are arranged in parallel Nicols.

Note that due to the characteristics of the polarizer, there is a transmission axis in a direction orthogonal to the absorption axis. Therefore, the case where the transmission axes are parallel to each other can also be referred to as parallel Nicol, and the case where the transmission axes are in an orthogonal state can also be referred to as crossed Nicol.

In FIG. 1, the number of layers including polarizers having different extinction coefficients is two, but the present invention is not limited to this and may have a multilayer structure. FIG. 7 shows an example in which a layer 121 including a fifth polarizer is further stacked on the layer 103 including the first polarizer and the layer 104 including the second polarizer having different extinction coefficients. In FIG. 7, the polarizer of the layer 121 including the fifth polarizer has an absorption axis (G), and the absorption axis (G) is the absorption axis (B) of the layer 104 including the second polarizer. And shifted from the absorption axis (A) of the layer 103 including the first polarizer. That is, as illustrated in FIG. 6A, the layer 121 including the fifth polarizer is stacked with the layer 104 including the second polarizer so that the absorption axes of the layers are parallel Nicols.

The extinction coefficient with respect to the absorption axis of the layer 121 including the fifth polarizer may be the same as or different from that of the layer 103 including the first polarizer or the layer 104 including the second polarizer. May be. In this embodiment mode, the extinction coefficient with respect to the absorption axis of the layer 121 including the fifth polarizer is different from that of the layer 103 including the first polarizer and the layer 104 including the second polarizer. . When the extinction coefficient with respect to the absorption axis of the polarizers thus laminated is made different, it is possible to widen the wavelength range to be absorbed, so that slight light leakage can be prevented. In the present invention, the layer including a plurality of stacked polarizers may have a stack in which the absorption axis of the polarizer is deviated from parallel Nicol. Similarly, a layer including a plurality of stacked polarizers may have at least two polarizers having different extinction coefficients.

Further, a layer including a fifth polarizer may be provided between the layer 103 including the first polarizer and the layer 104 including the second polarizer so as to be parallel Nicol. FIG. 8 illustrates an example in which a layer 122 including a fifth polarizer is further stacked between the layer 103 including the first polarizer and the layer 104 including the second polarizer. In FIG. 8, the polarizer of the layer 122 including the fifth polarizer has an absorption axis (H), and the absorption axis (H) is the absorption axis (A) of the layer 103 including the first polarizer. And shifted from the absorption axis (B) of the layer 104 containing the second polarizer. That is, as illustrated in FIG. 6B, the layer 122 including the fifth polarizer is stacked with the layer 103 including the first polarizer so that the absorption axes of the layers are parallel Nicols. The polarizer 104 and the layer 104 are stacked so that their absorption axes are shifted by a shift angle θ.

In addition, the layer 105 including the third polarizer and the layer 106 including the fourth polarizer may be stacked in a single layer (see FIG. 31). In this case, a stack of the layer 103 including the first polarizer and the layer 104 including the second polarizer having different extinction coefficients is disposed on the viewing side, and the third light source side is disposed on the light source side through the layer including the liquid crystal element. The layer 105 including the polarizer is arranged. The configuration as shown in FIG. 31 is preferably used when it is not particularly desired to reduce the amount of light from the light source.

As in this embodiment mode, a layer including a pair of stacked polarizers can be applied to a display device that can extract light from both sides of a substrate.

In such a layer including a pair of stacked polarizers, absorption is performed by stacking at least one of the polarizers with different extinction coefficients on the viewing side so that the absorption axes of the polarizers differ from parallel Nicols. Axial light leakage can be reduced. For this reason, the contrast ratio of the display device can be increased.

(Embodiment 2)
In this embodiment mode, a concept of a display device in which a retardation plate is provided in addition to a layer including a polarizer having a different extinction coefficient between a pair of stacked absorption axes will be described.

In FIG. 2A, one of a pair of stacked layers including polarizers having different extinction coefficients of absorption axes is stacked shifted from parallel Nicols, and the layer including the pair of polarizers and the substrate are stacked. FIG. 2B is a perspective view of the display device in which a retardation plate is provided between each of the display devices. In this embodiment, a liquid crystal display device including a liquid crystal element as a display element is described as an example.

As shown in FIG. 2A, a layer 100 having a liquid crystal element is sandwiched between a first substrate 101 and a second substrate 102 which are arranged to face each other.

As shown in FIG. 2A, a layer 103 including a first polarizer and a layer 104 including a second polarizer are provided on the first substrate 101 side. On the second substrate 102 side, a layer 105 including a third polarizer and a layer 106 including a fourth polarizer are provided.

As shown in FIG. 2B, the layer 103 including the first polarizer and the layer 104 including the second polarizer having different absorption coefficients of the absorption axis are arranged so as to be shifted from parallel Nicols. Furthermore, a retardation film 113 is provided between the first layer 101 and the layer including the polarizers having different extinction coefficients of the stacked absorption axes.

As shown in FIG. 2B, a layer 105 including a third polarizer and a layer 106 including a fourth polarizer are provided on the second substrate 102 side. The layer 105 including the third polarizer and the layer 106 including the fourth polarizer are arranged in parallel Nicols. Further, a phase difference plate 114 is provided between the stacked layer including the polarizer and the second substrate 102.

Although not shown in FIG. 2, the irradiation means such as a backlight is arranged below the layer 106 including the fourth polarizer.

Examples of the retardation plate include a film in which liquid crystal is hybrid-aligned, a film in which liquid crystal is twisted and aligned, a uniaxial retardation plate, or a biaxial retardation plate. Such a retardation plate can achieve a wide viewing angle of the display device. The film in which the liquid crystal is hybrid-aligned is a composite film in which a triacetyl cellulose (TAC) film is used as a support and a discotic liquid crystal having negative uniaxial property is hybrid-aligned to provide optical anisotropy.

The uniaxial retardation plate is formed by stretching a resin in one direction. The biaxial retardation plate is formed by uniaxially stretching the resin in the lateral direction and then weakly uniaxially stretching in the longitudinal direction. The resin used here is cycloolefin polymer (COE), polycarbonate (PC), polymethyl methacrylate (PMMA), polystyrene (PS), polyethersulfone (PES), polyphenylene sulfide (PPS), polyethylene terephthalate (PET). , Polyethylene naphthalate (PEN), polypropylene (PP), polyphenylene oxide (PPO), polyarylate (PAR), polyimide (PI), polytetrafluoroethylene (PTFE), and the like.

The film in which the liquid crystal is hybrid-aligned is a film formed by hybrid alignment of discotic liquid crystal or nematic liquid crystal with a triacetyl cellulose (TAC) film as a support. The retardation plate can be attached to the light-transmitting substrate in a state of being attached to a layer containing a polarizer.

By combining the retardation plate and the laminated polarizer, circularly polarized light, elliptically polarized light, or the like can be performed. In addition, a plurality of retardation plates may be used. Note that there is a fast axis in the direction orthogonal to the slow axis due to the characteristics of the retardation plate. Therefore, the arrangement can be determined based on the fast axis instead of the slow axis.

Note that in this embodiment, the layer 103 including the first polarizer and the layer 105 including the third polarizer are arranged so as to be crossed Nicols. As long as a predetermined black display is obtained, the layer 103 including the first polarizer and the layer 105 including the third polarizer may be deviated from the crossed Nicols state.

In FIG. 2, the number of layers including the polarizer is two, but the present invention is not limited to this and may have a multilayer structure. A layer including a fifth polarizer may be provided between the layer 103 including the first polarizer and the layer 104 including the second polarizer so as to be parallel Nicol. FIG. 11 illustrates an example in which a layer 122 including a fifth polarizer is further stacked over the layer 103 including the first polarizer and the layer 104 including the second polarizer. In FIG. 11, the polarizer of the layer 122 including the fifth polarizer has an absorption axis (H), and the absorption axis (H) is the absorption axis (A) of the layer 103 including the first polarizer. And shifted from the absorption axis (B) of the layer 104 containing the second polarizer. That is, the layer 122 including the fifth polarizer is stacked with the layer 103 including the first polarizer so that the absorption axes of the layers are parallel Nicols, and the layer 104 including the second polarizer is mutually absorbed. The layers are stacked so that the axis is shifted by a shift angle θ.

The extinction coefficient with respect to the absorption axis of the layer 122 including the fifth polarizer may be the same as or different from that of the layer 103 including the first polarizer or the layer 104 including the second polarizer. May be. In this embodiment mode, the extinction coefficient with respect to the absorption axis of the layer 122 including the fifth polarizer is different from that of the layer 103 including the first polarizer and the layer 104 including the second polarizer. . When the extinction coefficient with respect to the absorption axis of the polarizers thus laminated is made different, it is possible to widen the wavelength range to be absorbed, so that slight light leakage can be prevented.

As in this embodiment mode, a layer including a pair of stacked polarizers can be applied to a display device that can extract light from both sides of a substrate.

Thus a layer including a polarizer of the pair laminated, in a configuration having a phase difference plate, at least one, preferably from the viewing side, an absorption axis parallel nicol polarizers between different stacked with extinction coefficient By laminating so as to shift, light leakage in the absorption axis direction can be reduced. For this reason, the contrast ratio of the display device can be increased.

(Embodiment 3)
In this embodiment mode, a concept of a display device provided with a layer including a polarizer having a different extinction coefficient of an absorption axis stacked on the viewing side will be described, unlike the above embodiment mode. The same portions or portions having similar functions are denoted by the same reference numerals, and repeated description thereof is omitted.

3A is a cross-sectional view of a display device having a structure including stacked polarizers, in which the polarizers are shifted from parallel Nicols, and FIG. 3B shows the display. Figure 3 shows a perspective view of the device. In this embodiment, a liquid crystal display device including a liquid crystal element as a display element is described as an example.

As shown in FIG. 3A, a layer 100 having a liquid crystal element is sandwiched between a first substrate 101 and a second substrate 102 which are arranged to face each other.

On the outside of the substrate, that is, the side not in contact with the layer having the liquid crystal element, a layer including a stacked polarizer is provided. On the first substrate 101 side, a layer 103 including a first polarizer and a layer 104 including a second polarizer are provided. At this time, the absorption axes of the layer 103 including the first polarizer and the layer 104 including the second polarizer are shifted from parallel Nicols. In this embodiment mode, the extinction coefficient of the absorption axis of the layer 103 including the first polarizer and the layer 104 including the second polarizer are different.

In the present embodiment, it may be configured to further include a reflector. The reflecting plate can be provided by being provided outside the second substrate 102 or by forming the pixel electrode from a highly reflective material.

As shown in FIG. 3B, the absorption axis (A) of the layer 103 including the first polarizer and the absorption axis (B) of the layer 104 including the second polarizer are stacked to be shifted. Thus, the contrast ratio can be increased by laminating the layers including the polarizer while shifting the absorption axis.

In addition, by using the present invention and laminating and combining polarizers having different extinction coefficients with respect to the absorption axis, it is possible to eliminate or reduce the wavelength region where it is difficult to absorb light. Therefore, slight light leakage can be prevented and the contrast ratio can be further improved.

FIG. 3C is a top view of an angle formed by the absorption axis (A) of the layer 103 including the first polarizer and the absorption axis (B) of the layer 104 including the second polarizer. Indicates. The absorption axis (A) of the layer 103 including the first polarizer and the absorption axis (B) of the layer 104 including the second polarizer are stacked with a shift angle θ.

In FIG. 3, the number of layers including the polarizer is two, but the present invention is not limited to this and may have a multilayer structure. FIG. 9 illustrates an example in which a layer 121 including a fifth polarizer is further stacked over the layer 103 including the first polarizer and the layer 104 including the second polarizer. In FIG. 9, the polarizer of the layer 121 containing the fifth polarizer has an absorption axis (G), and the absorption axis (G) is the absorption axis (B) of the layer 104 containing the second polarizer. And shifted from the absorption axis (A) of the layer 103 including the first polarizer. That is, as illustrated in FIG. 9C, the layer 121 including the fifth polarizer is stacked with the layer 104 including the second polarizer so that the absorption axes thereof are parallel Nicols.

Further, a layer including a fifth polarizer may be provided between the layer 103 including the first polarizer and the layer 104 including the second polarizer so as to be parallel Nicol. FIG. 10 shows an example in which a layer 122 including a fifth polarizer is further stacked between the layer 103 including the first polarizer and the layer 104 including the second polarizer. In FIG. 10, the polarizer of the layer 122 including the fifth polarizer has an absorption axis (H), and the absorption axis (H) is the absorption axis (A) of the layer 103 including the first polarizer. And shifted from the absorption axis (B) of the layer 104 containing the second polarizer. That is, as illustrated in FIG. 10C, the layer 122 including the fifth polarizer is stacked with the layer 103 including the first polarizer so that the absorption axes of the layers are parallel Nicols. The polarizer 104 and the layer 104 are stacked so that their absorption axes are shifted by a shift angle θ.

The extinction coefficient with respect to the absorption axis of the layer 122 including the fifth polarizer may be the same as or different from that of the layer 103 including the first polarizer or the layer 104 including the second polarizer. May be. In this embodiment mode, the extinction coefficient with respect to the absorption axis of the layer 122 including the fifth polarizer is different from that of the layer 103 including the first polarizer and the layer 104 including the second polarizer. . When the extinction coefficient with respect to the absorption axis of the polarizers thus laminated is made different, it is possible to widen the wavelength range to be absorbed, so that slight light leakage can be prevented.

A structure having a layer including a polarizer stacked on one side of a substrate as in this embodiment mode can be applied to a display device that can extract light from one side of a substrate.

Thus, by laminating so that the absorption axes of polarizers having different extinction coefficients are deviated from parallel Nicols, light leakage in the absorption axis direction can be reduced. For this reason, the contrast ratio of the display device can be increased.

(Embodiment 4)
In this embodiment, unlike the above embodiment, a concept of a display device provided with a retardation plate in addition to a polarizer having a different extinction coefficient of an absorption axis stacked on the viewing side will be described. The same portions or portions having similar functions are denoted by the same reference numerals, and repeated description thereof is omitted.

4A is a cross-sectional view of a display device in which a retardation plate is provided between a substrate including a polarizer and a layer that is stacked with being shifted from parallel Nicols, and FIG. 4B illustrates the display. Figure 3 shows a perspective view of the device. In this embodiment, a liquid crystal display device including a liquid crystal element as a display element is described as an example.

As shown in FIG. 4A, a layer 100 having a liquid crystal element is sandwiched between a first substrate 101 and a second substrate 102 which are arranged to face each other.

As shown in FIG. 4A, a layer 103 including a first polarizer and a layer 104 including a second polarizer are provided on the first substrate 101 side. At this time, the layer 103 including the first polarizer and the layer 104 including the second polarizer are arranged so as to be shifted from parallel Nicols. Further, a retardation film 113 is provided between the layer including the stacked polarizers and the first substrate 101. In this embodiment mode, the extinction coefficient of the absorption axis of the layer 103 including the first polarizer and the layer 104 including the second polarizer are different.

In the present embodiment, it may be configured to further include a reflector. The reflecting plate can be provided by being provided outside the second substrate 102 or by forming the pixel electrode from a highly reflective material.

As shown in FIG. 4B, the absorption axis (A) of the layer 103 including the first polarizer is separated from the absorption axis (B) of the layer 104 including the second polarizer. Furthermore, the absorption axis (A) of the layer 103 including the first polarizer and the slow axis of the retardation film 113 may be arranged so as to be shifted by 45 °. Thus, the contrast ratio can be increased by stacking the layers including the polarizer while shifting the absorption axis and providing the retardation plate.

In FIG. 4, the number of layers including the polarizer is two, but the present invention is not limited to this and may have a multilayer structure. FIG. 12 illustrates an example in which a layer 122 including a fifth polarizer is further stacked over the layer 103 including the first polarizer and the layer 104 including the second polarizer. In FIG. 12, the polarizer of the layer 122 including the fifth polarizer has an absorption axis (G), and the absorption axis (G) is the absorption axis (B) of the layer 104 including the second polarizer. And shifted from the absorption axis (A) of the layer 103 including the first polarizer. That is, the layer 122 including the fifth polarizer is stacked with the layer 104 including the second polarizer so that the absorption axes of the layers are parallel Nicols.

The extinction coefficient with respect to the absorption axis of the layer 122 including the fifth polarizer may be the same as or different from that of the layer 103 including the first polarizer or the layer 104 including the second polarizer. May be. In this embodiment mode, the extinction coefficient with respect to the absorption axis of the layer 122 including the fifth polarizer is different from that of the layer 103 including the first polarizer and the layer 104 including the second polarizer. . When the extinction coefficient with respect to the absorption axis of the polarizers thus laminated is made different, it is possible to widen the wavelength range to be absorbed, so that slight light leakage can be prevented.

A structure having a layer including a polarizer stacked on one side of a substrate as in this embodiment mode can be applied to a display device that can extract light from one side of a substrate.

In this way, light leakage in the direction of the absorption axis can be reduced by stacking polarizers having different extinction coefficients so that the absorption axes deviate from parallel Nicols and further providing a retardation plate. For this reason, the contrast ratio of the display device can be increased.

(Embodiment 5)
In this embodiment mode, a structure of a polarizer having different extinction coefficients of stacked absorption axes that can be used in the present invention will be described with reference to FIGS.

In the present invention, the layer containing a polarizer only needs to include a polarizer having at least a specific absorption axis, and may be a single polarizer layer, or a protective layer is provided so as to sandwich the polarizer. It may be a structure. FIG. 13 shows an example of a laminated structure of layers including a polarizer in the present invention. FIG. 13A includes a layer including a polarizer including a protective layer 50a, a first polarizer 51, and a protective layer 50b, and a polarizer including a protective layer 50c, a second polarizer 52, and a protective layer 50d. The layer is a layer including a stacked polarizer. Thus, in the present invention, the stacked polarizers include those in which the polarizers are not directly stacked and stacked via a protective layer. Accordingly, the layer including the polarizers is a layer including a polarizer composed of the protective layer 50a, the first polarizer 51, and the protective layer 50b, a protective layer 50c, the second polarizer 52, and the protective layer 50d. The whole lamination | stacking with the layer containing the polarizer which consists of is also meant. In this specification, a layer including a polarizer including the protective layer 50a, the first polarizer 51, and the protective layer 50b is also referred to as a polarizing plate. Thus, FIG. 13A can also be referred to as a stack of polarizing plates. In FIG. 13A, the absorption axes of the first polarizer 51 and the second polarizer 52 are stacked while being shifted from each other. Further, the extinction coefficient values with respect to the absorption axes of the first polarizer 51 and the second polarizer 52 are different.

FIG. 13B illustrates a layer including a stacked polarizer formed by stacking a protective layer 56a, a first polarizer 57, a second polarizer 58, and a protective layer 56b. In the case of FIG. 13B, it can be said that a pair of protective layers 56a and 56b are provided so as to sandwich a stack of polarizers of the first polarizer 57 and the second polarizer 58, respectively. It can also be said that it is a laminate of a layer including a polarizer composed of the protective layer 56a and the polarizer 57 and a layer including a polarizer composed of the polarizer 58 and the protective layer 56b. FIG. 13B is an example in which the stacked polarizers in FIG. 13A are formed in direct contact with each other without a protective layer, and a layer including stacked polarizers that is a polarizing means. There is an advantage that the thickness can be reduced, and the number of protective layers may be reduced, so that the process is simplified at low cost. In FIG. 13B, the absorption axes of the first polarizer 57 and the second polarizer 58 are stacked in a shifted state. Moreover, the value of the extinction coefficient with respect to the absorption axis of the first polarizer 57 and the second polarizer 58 is different.

FIG. 13C illustrates an example in which polarizers are stacked with one protective layer interposed therebetween, and has a structure located between FIG. 13A and FIG. 13B. FIG. 13C illustrates a layer including a stacked polarizer including a protective layer 60a, a first polarizer 61, a protective layer 60b, a second polarizer 62, and a protective layer 60c. Thus, the structure which laminates | stacks a protective layer and a polarizer alternately may be sufficient. In the present invention, the polarizer is in the form of a film, and can be said to be a polarizing film or a polarizing layer. In FIG. 13C, the absorption axes of the first polarizer 61 and the second polarizer 62 are stacked while being shifted from each other. Moreover, the value of the extinction coefficient with respect to the absorption axis of the first polarizer 61 and the second polarizer 62 is different.

FIG. 13 shows an example in which two layers of polarizers are stacked. However, the polarizers may be stacked in three layers or more, and the method of providing a protective layer is not limited to that in FIG. Alternatively, a structure in which the layer including the stacked polarizers illustrated in FIG. 13B is stacked on the layer including the stacked polarizers illustrated in FIG. In the case of a polarizer that is more likely to deteriorate due to moisture or temperature changes depending on the material of the polarizer, the polarizer can be further protected by covering the polarizer with a protective layer as shown in FIG. 13A, improving reliability. Can be made. As shown in FIG. 1, when a polarizer is provided with a layer including a display element interposed therebetween, the laminated structure of the polarizer on the viewing side and the laminated structure of the polarizer on the opposite side with the display element interposed therebetween may be the same, It may be different. Thus, the laminated structure of the laminated polarizers can be set as appropriate depending on the characteristics of the polarizer and the functions required of the display device. For example, in Embodiment Mode 1, a layer including a polarizer is formed by laminating layers 103 and 104 including a polarizer and layers 105 and 106 including a polarizer, and the structure thereof is illustrated in FIGS. Any of (C) may be sufficient, and a different laminated structure may be used, one being FIG. 13 (A) and the other being FIG. 13 (B).

In addition, as a layer including the laminated polarizer, an adhesive layer (adhesive layer) may be provided to adhere the protective layers, the polarizers, and the protective layer to the polarizer, and the layers may be laminated via the adhesive layer. Good. In this case, the adhesive layer needs to have translucency like the protective layer. A retardation plate may be provided by laminating with a polarizer. The retardation plate may be a structure in which a retardation film is provided between a pair of protective layers, and may be laminated with a polarizer through a plurality or a single protective layer, or may be laminated directly with a polarizer to form a protective layer, a retardation A structure in which a film, a polarizer, and a protective layer are stacked in that order may be used. For example, in FIG. 13B, when the light transmitting substrate side is the protective layer 56a, a retardation film is provided between the protective layer 56a and the polarizer 57, and the retardation film is disposed between the light transmitting substrate and the polarizer. It is good also as a structure which provides. Furthermore, a more durable protective film or the like may be provided on the protective layer 50d, for example, as a surface protective layer, or an antireflection film that prevents reflection by external light on the screen surface, glare of the screen, and glare prevention. An anti-glare film may be provided. Moreover, when bonding the layer (polarizing plate) containing a polarizer to a board | substrate, adhesion layers, such as an acrylic adhesive, can be used.

The polarizer passes only light that vibrates in a certain direction and absorbs other light. A dichroic dye can be adsorbed and oriented on a uniaxially stretched resin film. PVA (polyvinyl alcohol) can be used as the resin. PVA has high transparency and strength, and is bonded to TAC (triacetyl cellulose) used as a protective layer (sometimes called a protective film because of its shape). Is also easy. As the pigment, iodine type and dye type can be used. For example, iodine-based dyes adsorb strong dichroic iodine as higher-order ions on a PVA resin film, and when stretched in an aqueous boric acid solution, iodine is arranged as a chain polymer, and the polarizer has high polarization characteristics. Indicates. On the other hand, the dye-based pigment uses a high dichroic dye instead of iodine, and is excellent in heat resistance and durability.

The protective layer reinforces the polarizer to prevent deterioration due to temperature and humidity. As the protective layer, a film such as TAC (triacetyl cellulose), COP (cyclic olefin polymer, PC (polycarbonate), etc. can be used.TAC is transparent, has a low birefringence, and is a PVA used for a polarizer. The COP system is a resin film having excellent heat resistance, moisture resistance and durability, and iodine and dye systems may be used in combination.

For example, as a layer containing a polarizer, an adhesive surface, TAC (triacetyl cellulose) as a protective layer, a mixed layer of PVA (polyvinyl alcohol) and iodine as a polarizer, and TAC as a protective layer are sequentially laminated from the substrate side. Other configurations can be used. The degree of polarization can be controlled by a mixed layer of PVA (polyvinyl alcohol) and iodine. An inorganic material may be used as the polarizer. Further, the layer containing a polarizer is sometimes called a polarizing plate because of its shape.

This embodiment can be used in combination with any of the above embodiments.

Thus, by laminating the polarizers so that the absorption axes of the polarizers having different extinction coefficients deviate from parallel Nicols, light leakage in the absorption axis direction can be reduced. For this reason, the contrast ratio of the display device can be increased.

(Embodiment 6)
In this embodiment, a pair of stacked absorption axes has a layer including a polarizer having different extinction coefficients, and at least one of the stacked layers including a polarizer has a configuration in which the absorption axis is shifted. A structure of the liquid crystal display device having the above will be described.

FIG. 16A is a top view illustrating a structure of a display panel according to the present invention, in which a pixel portion 2701 in which pixels 2702 are arranged in a matrix over a substrate 2700 having an insulating surface, a scanning line side input terminal 2703, a signal A line side input terminal 2704 is formed. The number of pixels may be provided in accordance with various standards. For full color display using XGA and RGB, 1024 × 768 × 3 (RGB), and for full color display using UXGA and RGB, 1600 × 1200. If it corresponds to x3 (RGB) and full spec high vision and is full color display using RGB, it may be 1920 x 1080 x 3 (RGB).

The pixels 2702 are arranged in a matrix by a scan line extending from the scan line side input terminal 2703 and a signal line extending from the signal line side input terminal 2704 intersecting. Each of the pixels 2702 includes a switching element and a pixel electrode layer connected to the switching element. A typical example of a switching element is a TFT. By connecting the gate electrode layer side of the TFT to a scanning line and the source or drain side to a signal line, each pixel can be controlled independently by a signal input from the outside. It is said.

FIG. 16A illustrates a structure of a display panel in which signals input to the scan lines and the signal lines are controlled by an external driver circuit. As illustrated in FIG. 17A, COG (Chip on The driver IC 2751 may be mounted on the substrate 2700 by a glass method. As another mounting mode, a TAB (Tape Automated Bonding) method as shown in FIG. 17B may be used. The driver IC may be formed on a single crystal semiconductor substrate or may be a circuit in which a TFT is formed on a glass substrate. In FIG. 17, the driver IC 2751 is connected to an FPC (Flexible printed circuit) 2750.

In the case where the TFT provided for the pixel is formed using a crystalline semiconductor, the scan line driver circuit 3702 can be formed over the substrate 3700 as shown in FIG. In FIG. 16B, the pixel portion 3701 is controlled by an external driver circuit as in FIG. 16A connected to the signal line side input terminal 3704. In the case where a TFT provided for a pixel is formed using a polycrystalline (microcrystalline) semiconductor, a single crystal semiconductor, or the like with high mobility, FIG. 16C illustrates a pixel portion 4701, a scan line driver circuit 4702, and a signal line driver circuit. 4704 can be integrally formed on the substrate 4700.

14A is a top view of a liquid crystal display device having a layer including stacked polarizers, and FIG. 14B is a cross-sectional view taken along line CD in FIG. 14A.

As shown in FIG. 14A, a pixel region 606, a driving circuit region 608a which is a scanning line driving circuit, and a driving circuit region 608b which is a scanning line driving region are formed between a substrate 600 and a counter substrate 695 by a sealant 692. A driving circuit region 607 which is a signal line driving circuit which is sealed in between and formed on the substrate 600 by an IC driver is provided. A transistor 622 and a capacitor 623 are provided in the pixel region 606, and a driver circuit including a transistor 620 and a transistor 621 is provided in the driver circuit region 608b. For the substrate 600, an insulating substrate similar to that in the above embodiment can be used. In general, substrates made of synthetic resin have a concern that the heat-resistant temperature is lower than other substrates, but they can also be adopted by transposing after a manufacturing process using a substrate with high heat resistance. Is possible.

In the pixel region 606, a transistor 622 serving as a switching element is provided through a base film 604a and a base film 604b. In this embodiment, a multi-gate thin film transistor (TFT) is used for the transistor 622, a semiconductor layer having an impurity region functioning as a source region and a drain region, a gate insulating layer, a gate electrode layer having a two-layer structure, a source An electrode layer and a drain electrode layer are included, and the source electrode layer or the drain electrode layer is in contact with and electrically connected to the impurity region of the semiconductor layer and the pixel electrode layer 630. Thin film transistors can be manufactured by a number of methods. For example, a crystalline semiconductor film is applied as the active layer. A gate electrode is provided over the crystalline semiconductor film with a gate insulating film interposed therebetween. An impurity element can be added to the active layer using the gate electrode. Thus, it is not necessary to form a mask for adding the impurity element by adding the impurity element using the gate electrode. The gate electrode can have a single-layer structure or a stacked structure. The impurity region can be a high concentration impurity region and a low concentration impurity region by controlling the concentration thereof. A thin film transistor having such a low concentration impurity region is referred to as an LDD (Lightly Doped Drain) structure. The low-concentration impurity region can be formed so as to overlap with the gate electrode. Such a thin film transistor is referred to as a GOLD (Gate Overlapped LDD) structure. The polarity of the thin film transistor is n-type by using phosphorus (P) or the like in the impurity region. When p-type is used, boron (B) or the like may be added. After that, an insulating film 611 and an insulating film 612 that cover the gate electrode and the like are formed. A dangling bond in the crystalline semiconductor film can be terminated by a hydrogen element mixed in the insulating film 611 (and the insulating film 612).

In order to further improve flatness, an insulating film 615 and an insulating film 616 may be formed as interlayer insulating films. For the insulating films 615 and 616, an organic material, an inorganic material, or a stacked structure thereof can be used. For example, silicon oxide, silicon nitride, silicon oxynitride, silicon nitride oxide, aluminum nitride, aluminum oxynitride, aluminum nitride oxide or aluminum oxide whose nitrogen content is higher than oxygen content, diamond like carbon (DLC), polysilazane, nitrogen content It can be formed of a material selected from carbon (CN), PSG (phosphorus glass), BPSG (phosphorus boron glass), alumina, and other inorganic insulating materials. An organic insulating material may be used, and the organic material may be either photosensitive or non-photosensitive, and polyimide, acrylic, polyamide, polyimide amide, resist, benzocyclobutene, siloxane resin, or the like can be used. . Note that a siloxane resin corresponds to a resin including a Si—O—Si bond. Siloxane has a skeleton structure formed of a bond of silicon (Si) and oxygen (O). As a substituent, an organic group containing at least hydrogen (for example, an alkyl group or an aromatic hydrocarbon) is used. A fluoro group may be used as a substituent. Alternatively, an organic group containing at least hydrogen and a fluoro group may be used as a substituent.
The

In addition, by using a crystalline semiconductor film, the pixel region and the driver circuit region can be formed over the same substrate. In that case, the transistor in the pixel portion and the transistor in the driver circuit region 608b are formed at the same time. Transistors used for the driver circuit region 608b constitute a CMOS circuit. Although the thin film transistor included in the CMOS circuit has a GOLD structure, an LDD structure such as the transistor 622 can also be used.

Without being limited to this embodiment mode, the thin film transistor in the pixel region may have a single gate structure in which one channel formation region is formed, a double gate structure in which two channel formation regions are formed, or a triple gate structure in which three channel formation regions are formed. . The thin film transistor in the peripheral driver circuit region may have a single gate structure, a double gate structure, or a triple gate structure.

Note that not only the method for manufacturing the thin film transistor described in this embodiment mode, but a top gate type (for example, a forward staggered type), a bottom gate type (for example, an inverted staggered type), or a gate insulating film above and below a channel region is used. The present invention can also be applied to a dual gate type or other structure having two gate electrode layers arranged.

Next, an insulating layer 631 called an alignment film is formed by a printing method or a spin coating method so as to cover the pixel electrode layer 630 and the insulating film 616. Note that the insulating layer 631 can be selectively formed by a screen printing method or an offset printing method. Thereafter, a rubbing process is performed. This rubbing process may not be performed in the liquid crystal mode, for example, the VA mode. The insulating layer 633 functioning as an alignment film is similar to the insulating layer 631. Subsequently, a sealant 692 is formed in a peripheral region where pixels are formed by a droplet discharge method.

After that, a counter substrate 695 provided with an insulating layer 633 functioning as an alignment film, a conductive layer 634 functioning as a counter electrode, a colored layer 635 functioning as a color filter, and a substrate 600 which is a TFT substrate are interposed through a spacer 637. The liquid crystal layer 632 is provided in the gap by bonding. After that, a stack of a layer 641 including a first polarizer and a layer 642 including a second polarizer is provided outside the counter substrate 695, and a third polarizer is provided on the opposite side of the substrate 600 having the element. A layer 643 including and a layer 644 including a fourth polarizer are provided. A layer 643 including a third polarizer and a layer 644 including a fourth polarizer are provided on the side opposite to the surface having the element of the substrate 600. A filler may be mixed in the sealing material, and a shielding film (black matrix) or the like may be formed on the counter substrate 695. Note that the color filter or the like may be formed from a material exhibiting red (R), green (G), and blue (B) when the liquid crystal display device is set to full color display. What is necessary is just to form from the material which exhibits a color.

Note that a color filter may not be provided when an RGB light emitting diode (LED) or the like is disposed in the backlight and a continuous additive color mixing method (field sequential method) in which color display is performed by time division is employed. The black matrix is preferably provided so as to overlap with the transistor or the CMOS circuit in order to reduce reflection of external light due to the wiring of the transistor or the CMOS circuit. Note that the black matrix may be formed so as to overlap with the capacitor. This is because reflection by the metal film constituting the capacitor element can be prevented.

As a method for forming the liquid crystal layer, a dispenser type (dropping type) or a dip type (pumping type) in which liquid crystal is injected using a capillary phenomenon after the substrate 600 having elements and the counter substrate 695 are bonded to each other is used. it can. The dropping method is preferably applied when handling a large substrate to which the injection method is difficult to apply.

The spacer may be provided by spraying particles of several μm, but in this embodiment, a method of forming a resin film on the entire surface of the substrate and then etching it is employed. After applying such a spacer material with a spinner, it is formed into a predetermined pattern by exposure and development processing. Further, it is cured by heating at 150 to 200 ° C. in a clean oven or the like. The spacers produced in this way can have different shapes depending on the conditions of exposure and development processing, but preferably, the spacers are columnar and the top is flat, so that the opposite substrate is When combined, the mechanical strength of the liquid crystal display device can be ensured. The shape can be a conical shape, a pyramid shape, or the like, and there is no particular limitation.

A connection portion is formed to connect the inside of the display device formed by the above steps and an external wiring board. The insulator layer in the connection portion is removed by ashing using oxygen gas at or near atmospheric pressure. This treatment is performed using oxygen gas and one or more selected from hydrogen, CF ₄ , NF ₃ , H ₂ O, and CHF ₃ . In this step, in order to prevent damage and destruction due to static electricity, ashing is performed after sealing using the counter substrate. .

Subsequently, an FPC 694 that is a wiring board for connection is provided on the terminal electrode layer 678 electrically connected to the pixel region with an anisotropic conductive layer 696 interposed therebetween. The FPC 694 plays a role of transmitting an external signal or potential. Through the above steps, a liquid crystal display device having a display function can be manufactured.

Note that a wiring included in the transistor, a gate electrode layer, a pixel electrode layer 630, and a conductive layer 634 which is a counter electrode layer include indium tin oxide (ITO), indium oxide and zinc oxide (ZnO) mixed in IZO (indium zinc oxide). Indium oxide mixed with silicon oxide (SiO ₂ ), indium oxide, organic tin, indium oxide containing tungsten oxide, indium zinc oxide containing tungsten oxide, indium oxide containing titanium oxide, titanium oxide Indium tin oxide containing, or tungsten (W), molybdenum (Mo), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), cobalt (Co ), Nickel (Ni), titanium (Ti), platinum (Pt ), Aluminum (Al), copper (Cu), or a metal thereof, an alloy thereof, or a metal nitride thereof.

The substrate 600 is provided by stacking a layer 643 including a third polarizer and a layer 644 including a fourth polarizer, and the counter substrate 695 also includes a layer 641 including the first polarizer and a second layer 644. A layer 642 including a polarizer is stacked. The layer 643 including the third polarizer and the layer 644 including the fourth polarizer provided on the backlight side are arranged in parallel Nicols, and include the first polarizer provided on the viewing side. 641 and the layer 642 including the second polarizer are arranged so as to deviate from parallel Nicols. The present invention is characterized in that the absorption axis of the laminated polarizer on one side, preferably the viewing side, of the pair of laminated polarizer- containing layers is shifted. As a result, the contrast ratio can be increased. Note that in this embodiment mode, the extinction coefficient of the absorption axis of the layer 641 including the first polarizer and the layer 642 including the second polarizer are different. Similarly, the extinction coefficient of the absorption axis of the layer 643 including the third polarizer and the layer 644 including the fourth polarizer are different.

The layer 643 including the third polarizer and the layer 644 including the fourth polarizer, the layer 641 including the first polarizer and the layer 642 including the second polarizer are stacked on the substrate 600, Bonded to the counter substrate 695. Moreover, you may laminate | stack in the state which had the phase difference plate between the layer containing the laminated | stacked polarizer, and a board | substrate.

The contrast ratio can be increased by providing a stacked polarizer with different extinction coefficients and shifting the absorption axis for such a display device. In the present invention, the plurality of polarizers can be a polarizer having a laminated structure, which is different from a structure in which the thickness of the polarizer is simply increased. By shifting the stacked polarizers, the contrast ratio can be increased as compared with a structure in which the film thickness is simply increased.

This embodiment mode can be freely combined with the above embodiment modes.

(Embodiment 7)
In this embodiment mode, a liquid crystal display device using a thin film transistor having an amorphous semiconductor film is described, which is different from the above embodiment mode. To do.

15 includes a transistor 220 which is an inverted staggered thin film transistor in a pixel region, a pixel electrode layer 201, an insulating layer 203, a liquid crystal layer 204, a spacer 281, an insulating layer 205, a counter electrode layer 206, Color filter 208, black matrix 207, counter substrate 210, layer 231 including a first polarizer, layer 232 including a second polarizer, layer 233 including a third polarizer, layer including a fourth polarizer 234, a sealing material 282, a terminal electrode layer 287, an anisotropic conductive layer 285, and an FPC 286 are provided in the sealing region.

A gate electrode layer, a source electrode layer, and a drain electrode layer of the transistor 220 which is an inverted staggered thin film transistor manufactured in this embodiment are formed by a droplet discharge method. The droplet discharge method is a method in which a composition having a liquid conductive material is discharged and solidified by drying or baking to form a conductive layer or an electrode layer. An insulating layer can also be formed by discharging a composition containing an insulating material and solidifying it by drying or baking. Since a structure of the display device such as a conductive layer or an insulating layer can be formed selectively, the process can be simplified and material loss can be prevented, so that the display device can be manufactured with low cost and high productivity.

In this embodiment mode, an amorphous semiconductor is used as a semiconductor layer, and a semiconductor layer having one conductivity type may be formed as needed. In this embodiment mode, an amorphous n-type semiconductor layer is stacked as a semiconductor layer and a semiconductor layer having one conductivity type. In addition, an n-type semiconductor layer is formed, an NMOS structure of an n-channel thin film transistor, a PMOS structure of a p-channel thin film transistor in which a p-type semiconductor layer is formed, and a CMOS structure of an n-channel thin film transistor and a p-channel thin film transistor. it can. In this embodiment, the transistor 220 is an n-channel inverted staggered thin film transistor. Alternatively, a channel-protective inverted staggered thin film transistor in which a protective layer is provided over the channel region of the semiconductor layer can be used.

In order to impart conductivity, an element imparting conductivity is added by doping, and an impurity region is formed in the semiconductor layer, whereby an n-channel thin film transistor or a P-channel thin film transistor can be formed. Instead of forming the n-type semiconductor layer, conductivity may be imparted to the semiconductor layer by performing plasma treatment with PH ₃ gas.

Alternatively, an organic semiconductor material can be used as a semiconductor and can be formed by a printing method, a spray method, a spin coating method, a droplet discharge method, a dispenser method, or the like. In this case, the number of processes can be reduced because the etching process is not necessary. As the organic semiconductor, a low molecular material, a polymer material, or the like is used, and materials such as an organic dye or a conductive polymer material can also be used. The organic semiconductor material used in the present invention is preferably a π-electron conjugated polymer material whose skeleton is composed of conjugated double bonds. Typically, a soluble polymer material such as polythiophene, polyfluorene, poly (3-alkylthiophene), a polythiophene derivative, or pentacene can be used.

Next, the configuration of the backlight unit 352 will be described. The backlight unit 352 includes a cold cathode tube, a hot cathode tube, a light emitting diode, an inorganic EL, and an organic EL as a light source 331 that emits fluorescence, a lamp reflector 332 for efficiently guiding the fluorescence to the light guide plate 335, and the fluorescence is totally reflected. While having a light guide plate 335 for guiding light to the entire surface of the display panel, a diffusion plate 336 for reducing unevenness in brightness, and a reflection plate 334 for reusing light leaked under the light guide plate 335. Has been.

A control circuit for adjusting the luminance of the light source 331 is connected to the backlight unit 352. The luminance of the light source 331 can be controlled by supplying a signal from the control circuit.

A layer 233 including a third polarizer and a layer 234 including a fourth polarizer are stacked between the substrate 200 and the backlight unit 352, and the counter substrate 210 also includes the first polarizer. A layer 232 including 231 and a second polarizer is stacked. The layer 233 including the third polarizer and the layer 234 including the fourth polarizer provided on the backlight side are arranged in parallel Nicols, and include the first polarizer provided on the viewing side. In the present invention, the layer 232 including the 231 and the second polarizer is disposed so as to deviate from parallel Nicols, and one of the layers including a pair of stacked polarizers, preferably stacked on the viewing side. The layer including the polarizer is shifted. As a result, the contrast ratio can be increased. Note that in this embodiment mode, the extinction coefficient of the absorption axis of the layer 231 including the first polarizer and the layer 232 including the second polarizer are different. Similarly, the extinction coefficient of the absorption axis of the layer 233 including the third polarizer and the layer 234 including the fourth polarizer are different.

The layer 233 including the third polarizer and the layer 234 including the fourth polarizer, the layer 231 including the first polarizer and the layer 232 including the second polarizer are the substrate 200, Bonded to the counter substrate 210. Moreover, you may laminate | stack in the state which had the phase difference plate between the layer containing the laminated | stacked polarizer, and a board | substrate.

The contrast ratio can be increased by providing a laminated polarizer with different extinction coefficients and shifting the absorption axis for such a liquid crystal display device. In the present invention, the plurality of polarizers can be a layer including a polarizer having a laminated structure, which is different from a structure in which the thickness of the polarizer is simply increased. By shifting the stacked polarizers, the contrast ratio can be increased as compared with a structure in which the film thickness is simply increased.

This embodiment mode can be freely combined with the above embodiment modes.

(Embodiment 8)
In this embodiment mode, operations of circuits and the like included in the display device are described.

FIG. 24 is a system block diagram of the pixel portion 505 and the driver circuit portion 508 of the display device.

The pixel portion 505 includes a plurality of pixels, and a switching element is provided in an intersection region between the signal line 512 serving as each pixel and the scanning line 510. Application of a voltage for controlling the tilt of liquid crystal molecules can be controlled by the switching element. A structure in which switching elements are provided in each intersection region in this way is called an active type. The pixel portion of the present invention is not limited to such an active type, and may have a passive configuration. Since the passive type has no switching element in each pixel, the process is simple.

The driver circuit portion 508 includes a control circuit 502, a signal line driver circuit 503, and a scanning line driver circuit 504. The control circuit 502 has a function of performing gradation control in accordance with display contents of the pixel portion 505. Therefore, the control circuit 502 inputs the generated signal to the signal line driver circuit 503 and the scan line driver circuit 504. When a switching element is selected via the scanning line 510 based on the scanning line driving circuit 504, a voltage is applied to the pixel electrode in the selected intersection region. The value of this voltage is determined based on a signal input from the signal line driver circuit 503 via the signal line.

Further, the control circuit 502 generates a signal for controlling the power supplied to the lighting unit 506, and the signal is input to the power source 507 of the lighting unit 506. The backlight unit described in the above embodiment can be used as the illumination unit. The illumination means includes a front light in addition to the backlight. The front light is a plate-like light unit that is mounted on the front side of the pixel portion and is composed of a light emitter and a light guide that illuminate the whole. Such illumination means can illuminate the pixel portion evenly with low power consumption.

As illustrated in FIG. 24B, the scan line driver circuit 504 includes circuits that function as a shift register 541, a level shifter 542, and a buffer 543. Signals such as a gate start pulse (GSP) and a gate clock signal (GCK) are input to the shift register 541. Note that the scan line driver circuit of the present invention is not limited to the structure shown in FIG.

As shown in FIG. 24C, the signal line driver circuit 503 includes circuits that function as a shift register 531, a first latch 532, a second latch 533, a level shifter 534, and a buffer 535. The circuit functioning as the buffer 535 is a circuit having a function of amplifying a weak signal and includes an operational amplifier or the like. A signal such as a start pulse (SSP) is input to the level shifter 534, and data (DATA) such as a video signal is input to the first latch 532. A latch (LAT) signal can be temporarily held in the second latch 533 and is input to the pixel portion 505 all at once. This is called line sequential driving. Therefore, the second latch can be omitted if the pixel performs dot sequential driving instead of line sequential driving. As described above, the signal line driver circuit of the present invention is not limited to the structure shown in FIG.

The signal line driver circuit 503, the scan line driver circuit 504, and the pixel portion 505 can be formed using semiconductor elements provided over the same substrate. The semiconductor element can be formed using a thin film transistor provided over a glass substrate. In this case, a crystalline semiconductor film is preferably used for the semiconductor element (see Embodiment Mode 6). Since the crystalline semiconductor film has high electrical characteristics, particularly mobility, a circuit included in the driver circuit portion can be formed. In addition, the signal line driver circuit 503 and the scan line driver circuit 504 can be mounted on a substrate using an IC (Integrated Circuit) chip. In this case, an amorphous semiconductor film can be applied to the semiconductor element in the pixel portion (see Embodiment Mode 7).

In such a display device, it is possible to increase the contrast ratio by providing stacked polarizers having different extinction coefficients and shifting the absorption axis. That is, the contrast ratio of light from the illumination means controlled by the control circuit can be increased.

(Embodiment 9)
In this embodiment, a structure of a backlight is described. The backlight is provided in the display device as a backlight unit having a light source, and the light source is surrounded by a reflector so that the backlight unit efficiently scatters light.

As shown in FIG. 19A, the backlight unit 352 can use a cold cathode tube 401 as a light source. In addition, a lamp reflector 332 can be provided in order to reflect light from the cold cathode tube 401 efficiently. The cold cathode tube 401 is often used for a large display device. This is due to the intensity of the luminance from the cold cathode tube. Therefore, a backlight unit having a cold cathode tube can be used for a display of a personal computer.

As shown in FIG. 19B, the backlight unit 352 can use a light emitting diode (LED) 402 as a light source. For example, light emitting diodes (W) 402 that emit white light are arranged at predetermined intervals. In addition, a lamp reflector 332 can be provided in order to efficiently reflect light from the light emitting diode (W) 402.

As shown in FIG. 19C, the backlight unit 352 can use light-emitting diodes (LEDs) 403, 404, and 405 of each color RGB as light sources. By using the light emitting diodes (LEDs) 403, 404, and 405 of each color RGB, color reproducibility can be improved as compared with only the light emitting diode (W) 402 that emits white. In addition, a lamp reflector 332 can be provided in order to efficiently reflect light from the light emitting diode (W) 402.

Furthermore, as shown in FIG. 19D, when light-emitting diodes (LEDs) 403, 404, and 405 of each color RGB are used as the light source, it is not necessary to make the number and arrangement thereof the same. For example, a plurality of colors with low emission intensity (for example, green) may be arranged.

Further, a light emitting diode 402 that emits white and a light emitting diode (LED) 403, 404, and 405 of each color RGB may be used in combination.

In the case of having RGB light emitting diodes, when the field sequential mode is applied, color display can be performed by sequentially lighting the RGB light emitting diodes according to time.

When a light-emitting diode is used, it has high luminance and is suitable for a large display device. Further, since the color purity of each of the RGB colors is good, the color reproducibility is superior to that of the cold cathode tube, and the arrangement area can be reduced. Therefore, when the display is adapted to a small display device, the frame can be narrowed.

Further, it is not always necessary to arrange the light source as the backlight unit shown in FIG. For example, when a backlight having a light emitting diode is mounted on a large display device, the light emitting diode can be disposed on the back surface of the substrate. At this time, the light emitting diodes can maintain predetermined intervals, and the light emitting diodes of the respective colors can be arranged in order. The color reproducibility can be improved by the arrangement of the light emitting diodes.

A display device using such a backlight is provided with a layer including stacked polarizers, and the absorption axes of the polarizers are shifted so that an image with a high contrast ratio can be provided. . In particular, a backlight including a light-emitting diode is suitable for a large display device, and a high-quality image can be provided even in a dark place by increasing the contrast ratio of the large display device.

(Embodiment 10)
In the liquid crystal display device, there are a vertical electric field method in which a voltage is applied perpendicular to the substrate and a horizontal electric field method in which a voltage is applied in parallel to the substrate. A structure in which a layer including a polarizer which is stacked and arranged with the absorption axis shifted is applicable to either a vertical electric field method or a horizontal electric field method. Therefore, in this embodiment mode, various liquid crystal modes to which a layer including polarizers stacked and arranged with the absorption axis shifted may be applied.

First, FIGS. 27A1 and 27A2 are schematic views of a TN mode liquid crystal display device.

Similarly to the above embodiment mode, a layer 100 having a display element is sandwiched between a first substrate 101 and a second substrate 102 which are arranged to face each other. On the first substrate 101 side, a layer 103 including a first polarizer and a layer 104 including a second polarizer are arranged so as to be shifted from parallel Nicols. On the second substrate 102 side, a layer 105 including a third polarizer and a layer 106 including a fourth polarizer are arranged in parallel Nicols. Note that the layer 103 including the first polarizer and the layer 105 including the third polarizer are arranged so as to be crossed Nicols.

Although not shown, the backlight or the like is disposed outside the layer including the fourth polarizer. A first electrode 108 and a second electrode 109 are provided over the first substrate 101 and the second substrate 102, respectively. In addition, the first electrode 108 which is an electrode on the side opposite to the backlight, that is, the viewing side is formed so as to have at least translucency.

In the liquid crystal display device having such a structure, in the normally white mode, when voltage is applied to the first electrode 108 and the second electrode 109 (referred to as a vertical electric field mode), the state illustrated in FIG. As shown, black display is performed. At this time, the liquid crystal molecules are aligned vertically. As a result, the light from the backlight cannot pass through the substrate, resulting in a black display.

As shown in FIG. 27A2, when a voltage is not applied between the first electrode 108 and the second electrode 109, white display is performed. At this time, the liquid crystal molecules are aligned side by side and twisted in a plane. As a result, the light from the backlight is a layer including a pair of stacked polarizers, and can pass through a substrate arranged by shifting the layer including the stacked polarizers on the viewing side from parallel Nicols. And a predetermined video display is performed.

At this time, a full color display can be performed by providing a color filter. The color filter can be provided on either the first substrate 101 side or the second substrate 102 side.

A known liquid crystal material may be used for the TN mode.

FIG. 27B1 is a schematic view of a VA mode liquid crystal display device. The VA mode is a mode in which liquid crystal molecules are aligned so as to be perpendicular to the substrate when there is no electric field.

As in FIGS. 27A1 and 27A2, the first electrode 108 and the second electrode 109 are provided over the first substrate 101 and the second substrate 102, respectively. In addition, the first electrode 108 which is an electrode on the side opposite to the backlight, that is, the viewing side is formed so as to have at least translucency. The layer 103 including the first polarizer and the layer 104 including the second polarizer are arranged so as to be shifted from parallel Nicols. On the second substrate 102 side, a layer 105 including a third polarizer and a layer 106 including a fourth polarizer are arranged in parallel Nicols. Note that the layer 103 including the first polarizer and the layer 105 including the third polarizer are arranged so as to be crossed Nicols.

In a liquid crystal display device having such a structure, when voltage is applied to the first electrode 108 and the second electrode 109 (vertical electric field method), white display is performed as shown in FIG. It becomes a state. At this time, the liquid crystal molecules are arranged side by side. Then, the light from the backlight can pass through a substrate provided with a layer including a polarizer that is stacked and deviated from parallel Nicols, and a predetermined video display is performed. At this time, a full color display can be performed by providing a color filter. The color filter can be provided on either the first substrate 101 side or the second substrate 102 side.

As shown in FIG. 27B2, when no voltage is applied between the first electrode 108 and the second electrode 109, black display, that is, an off state is obtained. At this time, the liquid crystal molecules are aligned vertically. As a result, the light from the backlight cannot pass through the substrate, resulting in a black display.

Thus, in the off state, the liquid crystal molecules rise perpendicularly to the substrate and display black, and in the on state, the liquid crystal molecules tilt horizontally with respect to the substrate and display white. Since the liquid crystal molecules are standing up in the off state, the light from the polarized backlight passes through the cell without being affected by the liquid crystal molecules, and is completely blocked by the layer containing the polarizer on the counter substrate side. Can do. For this reason, the contrast ratio is expected to be further improved by disposing at least one of the stacked polarizer layers including the stacked polarizers from the parallel Nicols.

FIGS. 27C1 and 27C2 illustrate examples in which the layer including the stacked polarizer of the present invention is applied to the MVA mode in which the alignment of the liquid crystal is divided. The MVA mode is a method in which one pixel is divided into a plurality of parts and the viewing angle dependence of each part is compensated for each other. As shown in FIG. 27C1, in the MVA mode, protrusions 158 and 159 having a triangular section are provided on the first electrode 108 and the second electrode 109 for alignment control. When voltage is applied to the first electrode 108 and the second electrode 109 (vertical electric field method), an on state in which white display is performed is performed as shown in FIG. 27C1. At this time, the liquid crystal molecules are tilted with respect to the protrusions 158 and 159. Then, the light from the backlight can pass through a substrate provided with a layer including a polarizer that is stacked and deviated from parallel Nicols, and a predetermined video display is performed. At this time, a full color display can be performed by providing a color filter. The color filter can be provided on either the first substrate 101 side or the second substrate 102 side.

Then, as shown in FIG. 27C2, when no voltage is applied between the first electrode 108 and the second electrode 109, black display is performed, that is, an off state is obtained. At this time, the liquid crystal molecules are aligned vertically. As a result, the light from the backlight cannot pass through the substrate, resulting in a black display.

FIG. 30 shows a top view and a cross-sectional view of another example of the MVA mode. In FIG. 30A, the second electrode is formed in a bent pattern like a dogleg shape and becomes the second electrodes 109a, 109b, 109c. An insulating layer 162 that is an alignment film is formed over the second electrodes 109a, 109b, and 109c. As shown in FIG. 30B, a protrusion 158 is formed over the first electrode 108 so as to correspond to the second electrodes 109a, 109b, and 109c. The openings of the second electrodes 109a, 109b, and 109c function as protrusions. The liquid crystal molecules can be moved.

28A1 and 28A2 are schematic views of an OCB mode liquid crystal display device. In the OCB mode, the alignment of liquid crystal molecules forms an optically compensated state in the liquid crystal layer, which is called bend alignment.

As in FIG. 27, a first electrode 108 and a second electrode 109 are provided over the first substrate 101 and the second substrate 102, respectively. Although not illustrated, the backlight or the like is disposed outside the layer 106 including the fourth polarizer. In addition, the first electrode 108 which is an electrode on the side opposite to the backlight, that is, the viewing side is formed so as to have at least translucency. The layer 103 including the first polarizer and the layer 104 including the second polarizer are arranged so as to be shifted from parallel Nicols. On the second substrate 102 side, a layer 105 including a third polarizer and a layer 106 including a fourth polarizer are arranged in parallel Nicols. Note that the layer 103 including the first polarizer and the layer 105 including the third polarizer are arranged so as to be crossed Nicols.

In the liquid crystal display device having such a structure, when a certain on-voltage is applied to the first electrode 108 and the second electrode 109 (vertical electric field method), black display is obtained as shown in FIG. Done. At this time, the liquid crystal molecules are aligned vertically. Then, the light from the backlight cannot pass through the substrate, and a black display is obtained.

Then, as shown in FIG. 28A2, when a constant off voltage is applied between the first electrode 108 and the second electrode 109, white display is performed. At this time, the liquid crystal molecules are in a bent alignment state. As a result, light from the backlight can pass through a substrate provided with a layer including a stacked polarizer, and a predetermined video display is performed. At this time, a full color display can be performed by providing a color filter. The color filter can be provided on either the first substrate 101 side or the second substrate 102 side.

In such an OCB mode, the birefringence generated in the liquid crystal layer is a layer including a pair of stacked polarizers, and the layer including the stacked polarizers is shifted from parallel Nicols on the viewing side. Can be compensated. As a result, the contrast ratio can be increased in addition to the wide viewing angle.

FIGS. 28B1 and 28B2 are schematic diagrams of liquid crystals in the FLC mode and the AFLC mode.

As in FIG. 27, a first electrode 108 and a second electrode 109 are provided over the first substrate 101 and the second substrate 102, respectively. In addition, the first electrode 108 which is an electrode on the side opposite to the backlight, that is, the viewing side is formed so as to have at least translucency. The layer 103 including the first polarizer and the layer 104 including the second polarizer are arranged so as to be shifted from parallel Nicols. On the second substrate 102 side, a layer 105 including a third polarizer and a layer 106 including a fourth polarizer are arranged in parallel Nicols. Note that the layer 103 including the first polarizer and the layer 105 including the third polarizer are arranged so as to be crossed Nicols.

In the liquid crystal display device having such a structure, when voltage is applied to the first electrode 108 and the second electrode 109 (referred to as a vertical electric field mode), white display is performed as illustrated in FIG. Become. At this time, the liquid crystal molecules are aligned horizontally and are rotated in a plane. As a result, the light from the backlight is a layer including a pair of stacked polarizers, and passes through the substrate disposed on the viewer side so that the layer including the stacked polarizers is shifted from parallel Nicols. And a predetermined video display is performed.

Then, as shown in FIG. 28B2, when no voltage is applied between the first electrode 108 and the second electrode 109, black display is performed. At this time, the liquid crystal molecules are arranged side by side. As a result, the light from the backlight cannot pass through the substrate, resulting in a black display.

At this time, a full color display can be performed by providing a color filter. The color filter can be provided on either the first substrate 101 side or the second substrate 102 side.

As the liquid crystal material used in the FLC mode and the AFLC mode, a known material may be used.

29A1 and 29A2 are schematic views of an IPS mode liquid crystal display device. The IPS mode is a mode in which liquid crystal molecules are always rotated in a plane with respect to a substrate, and an electrode adopts a horizontal electric field method provided only on one substrate side.

The IPS mode is characterized in that the liquid crystal is controlled by a pair of electrodes provided on one substrate. Therefore, a pair of electrodes 150 and 151 is provided over the second substrate 102. The pair of electrodes 150 and 151 preferably have a light-transmitting property. The layer 103 including the first polarizer and the layer 104 including the second polarizer are arranged so as to be shifted from parallel Nicols. On the second substrate 102 side, a layer 105 including a third polarizer and a layer 106 including a fourth polarizer are arranged in parallel Nicols. Note that the layer 103 including the first polarizer and the layer 105 including the third polarizer are arranged so as to be crossed Nicols. Although not illustrated, the backlight or the like is disposed outside the layer 106 including the fourth polarizer.

In the liquid crystal display device having such a structure, when voltage is applied to the pair of electrodes 150 and 151, an on state in which white display is performed is performed as illustrated in FIG. Then, the light from the backlight is a layer including a pair of stacked polarizers, and can pass through a substrate in which the layer including the polarizers stacked on the viewing side is arranged out of parallel Nicol, A predetermined video display is performed.

At this time, a full color display can be performed by providing a color filter. The color filter can be provided on either the first substrate 101 side or the second substrate 102 side.

Then, as shown in FIG. 29A2, when no voltage is applied between the pair of electrodes 150 and 151, black display, that is, an off state is obtained. At this time, the liquid crystal molecules are arranged side by side and rotated in a plane. As a result, the light from the backlight cannot pass through the substrate, resulting in a black display.

An example of a pair of electrodes 150 and 151 that can be used in the IPS mode is shown in FIG. As shown in the top views of FIGS. 25A to 25D, the pair of electrodes 150 and 151 are formed so as to alternate with each other. In FIG. 25A, the electrode 150a and the electrode 151a have undulations. In FIG. 25B, the electrode 150b and the electrode 151b have concentric openings, and in FIG. 25C, the electrode 150c and the electrode 151c have a comb shape and are partially overlapped. In FIG. 25D, the electrode 150d and the electrode 151d are comb-shaped and have a shape in which the electrodes are engaged with each other.

In addition to the IPS mode, an FFS mode can also be used. In the IPS mode, the pair of electrodes are formed on the same surface in the IPS mode, whereas the pair of electrodes are not formed on the same layer, and are insulated on the electrode 152 as shown in FIGS. 29B1 and 29B2. In this structure, the electrode 153 is formed through a film.

In the liquid crystal display device having such a structure, when voltage is applied to the pair of electrodes 152 and 153, an on state in which white display is performed is performed as illustrated in FIG. Then, the light from the backlight is a layer including a pair of stacked polarizers, and can pass through a substrate in which the layer including the polarizers stacked on the viewing side is arranged out of parallel Nicol, A predetermined video display is performed.

At this time, a full color display can be performed by providing a color filter. The color filter can be provided on either the first substrate 101 side or the second substrate 102 side.

Then, as shown in FIG. 29B2, when no voltage is applied between the pair of electrodes 152 and 153, black display is performed, that is, an off state is obtained. At this time, the liquid crystal molecules are arranged side by side and rotated in a plane. As a result, the light from the backlight cannot pass through the substrate, resulting in a black display.

An example of a pair of electrodes 152 and 153 that can be used in the FFS mode is shown in FIG. 26A to 26D, electrodes 153 formed in various patterns are formed over the electrode 152. In FIG. 26A, the electrode 153a on the electrode 152a is bent. In FIG. 26B, the electrode 153b on the electrode 152b has a concentric shape, and in FIG. 26C, the electrode 151c on the electrode 150c has a comb shape so that the electrodes mesh with each other. In FIG. 26D, the electrode 153d on the electrode 152d has a comb-like shape.

As the liquid crystal material used for the IPS mode and the FFS mode, a known material may be used.

When a configuration including a pair of laminated polarizers according to the present invention, in which the layer containing the polarizers laminated on the viewing side is shifted from parallel Nicols, is applied to a vertical electric field type liquid crystal display device, Further high contrast ratio display can be performed. Such a vertical electric field method is suitable for a computer display device or a large television used indoors.

Further, when the present invention is applied to a horizontal electric field type liquid crystal display device, a display with a high contrast ratio can be achieved in addition to a wide viewing angle. Such a horizontal electric field method is suitable for a portable display device.

In addition, the present invention can be applied to a liquid crystal display device in an optical rotation mode, a scattering mode, and a birefringence mode, and a display device in which layers including a polarizer are arranged on both sides of a substrate.

This embodiment mode can be freely combined with the above embodiment modes.

(Embodiment 11)
This embodiment will be described with reference to FIGS. 18A and 18B. FIG. 18A and FIG. 18B illustrate an example in which a display device (a liquid crystal display module) is formed using a TFT substrate 2600 manufactured by applying the present invention.

FIG. 18A illustrates an example of a liquid crystal display module. A TFT substrate 2600 and a counter substrate 2601 are fixed to each other with a sealant 2602, and a pixel portion 2603 including a TFT or the like and a liquid crystal layer 2604 are provided therebetween to form a display region. ing. The colored layer 2605 is necessary for color display. In the case of the RGB method, a colored layer corresponding to each color of red, green, and blue is provided corresponding to each pixel. Outside the TFT substrate 2600 and the counter substrate 2601, a layer 2606 containing a first polarizer, a layer 2626 containing a second polarizer, a layer 2607 containing a third polarizer, and a layer 2627 containing a fourth polarizer A lens film 2613 is provided. The light source is composed of a cold cathode tube 2610 and a reflection plate 2611. The circuit board 2612 is connected to the TFT substrate 2600 by a flexible wiring board 2609, and an external circuit such as a control circuit or a power supply circuit is incorporated.

Between the TFT substrate 2600 and the backlight as the light source, a layer 2607 including a third polarizer and a layer 2627 including a fourth polarizer, which have different extinction coefficients of absorption axes, are provided to be stacked. A layer 2606 including a first polarizer and a layer 2626 including a second polarizer, which have different absorption coefficients of absorption axes from each other, are stacked in 2601. A layer 2607 including a third polarizer and a layer 2627 including a fourth polarizer provided on the backlight side are arranged so as to be parallel Nicols, and include a first polarizer provided on the viewing side. In the present invention, the layer 2626 including 2606 and the second polarizer is arranged so as to deviate from parallel Nicol. In the present invention, either one of a pair of stacked layers including polarizers having different extinction coefficients of absorption axes. Preferably, the layer including the polarizer laminated on the viewing side is shifted. As a result, the contrast ratio can be increased.

The layer 2607 including the third polarizer and the layer 2627 including the fourth polarizer, the layer 2606 including the first polarizer and the layer 2626 including the second polarizer are stacked on the TFT substrate 2600. Is bonded to the counter substrate 2601. Moreover, you may laminate | stack in the state which had the phase difference plate between the layer containing the laminated | stacked polarizer, and a board | substrate.

The liquid crystal display module includes TN (Twisted Nematic), IPS (In-Plane-Switching) mode, FFS (Fringe Field Switching) mode, MVA (Multi-domain Vertical Alignment) mode, ASM (Axial Asymmetrical). A mode, an OCB (Optical Compensated Birefringence, or Optically Compensated Bend) mode, an FLC (Ferroelectric Liquid Crystal) mode, or the like can be used.

FIG. 18B is an example in which the OCB mode is applied to the liquid crystal display module of FIG. 18A, and is an FS-LCD (Field sequential-LCD). The FS-LCD emits red light, green light, and blue light in one frame period, and can perform color display by combining images using time division. Further, since each light emission is performed by a light emitting diode or a cold cathode tube, a color filter is unnecessary. Therefore, it is not necessary to arrange the color filters of the three primary colors and limit the display area of each color, and since all three colors can be displayed in any area, nine times as many pixels can be displayed in the same area. On the other hand, since the three colors emit light in one frame period, a high-speed response of the liquid crystal is required. By applying the FS mode, the FLC mode, and the OCB mode to the display device of the present invention, a high-performance and high-quality display device or a liquid crystal television device can be completed.

The liquid crystal layer in the OCB mode has a so-called π cell structure. The π cell structure is a structure in which the pretilt angles of liquid crystal molecules are aligned in a plane-symmetric relationship with respect to the center plane between the active matrix substrate and the counter substrate. The alignment state of the π cell structure is splay alignment when no voltage is applied between the substrates, and shifts to bend alignment when a voltage is applied. When a voltage is further applied, the bend-aligned liquid crystal molecules are aligned perpendicularly to both substrates, and light is not transmitted. In the OCB mode, high-speed response that is about 10 times faster than the conventional TN mode can be realized.

Further, as a mode corresponding to the FS mode, HV-FLC, SS-FLC, or the like using a ferroelectric liquid crystal (FLC) capable of high-speed operation can be used. In the OCB mode, nematic liquid crystal having a relatively low viscosity is used, and smectic liquid crystal is used in HV-FLC and SS-FLC, and materials such as FLC, nematic liquid crystal, and smectic liquid crystal may be used as the liquid crystal material. it can.

In addition, the high-speed optical response speed of the liquid crystal display module is increased by narrowing the cell gap of the liquid crystal display module. The speed can also be increased by reducing the viscosity of the liquid crystal material. The increase in speed is more effective when the pixel in the pixel region of the TN mode liquid crystal display module or the dot pitch is 30 μm or less.

The liquid crystal display module in FIG. 18B is a transmissive liquid crystal display module, and is provided with a red light source 2910a, a green light source 2910b, and a blue light source 2910c as light sources. The light source is provided with a controller 2912 for controlling on / off of the red light source 2910a, the green light source 2910b, and the blue light source 2910c. The light emission of each color is controlled by the control unit 2912, light enters the liquid crystal, an image is synthesized using time division, and color display is performed.

By laminating the layers including the polarizers so that the absorption axes of the polarizers having different extinction coefficients are deviated from parallel Nicols, light leakage in the absorption axis direction can be reduced. For this reason, the contrast ratio of the display device can be increased. Thus, a high-performance and high-quality display device can be manufactured.

This embodiment can be used in combination with any of the above embodiments.

(Embodiment 12)
This embodiment will be described with reference to FIG. FIG. 23 shows an example in which a display device is formed using a substrate 813 which is a TFT substrate manufactured by applying the present invention.

23 includes a substrate 813, a pixel portion 814 including a TFT, a liquid crystal layer 815, a counter substrate 816, a layer 817 including a first polarizer, a layer 818 including a second polarizer, and a third polarizer. A display unit 801 including a layer 811, a layer 812 including a fourth polarizer, a slit (grating) 850, a driver circuit 819, and an FPC 837, a light source 831, a lamp reflector 832, a reflection plate 834, a light guide plate 835, and a diffusion plate A backlight unit 802 including 836 is shown.

The display device of the present invention shown in FIG. 23 can perform three-dimensional display without using special equipment such as glasses. The slit 850 having an opening disposed on the backlight unit side transmits light incident from the light source in a stripe shape and allows the light to enter the display device unit 801. The slit 850 can create a parallax between both eyes of the viewer on the viewer side, and the viewer sees only the right-eye pixel in the right eye and the left-eye pixel in the left eye at the same time. Therefore, the viewer can see the three-dimensional display. That is, in the display device unit 801, the light given a specific viewing angle by the slit 850 passes through pixels corresponding to the right-eye image and the left-eye image, so that the right-eye image and the left-eye image are different. Separated into viewing angles, three-dimensional display is performed.

A layer 811 including a third polarizer and a layer 812 including a fourth polarizer are provided between the substrate 813 and a backlight which is a light source, and the counter substrate 816 includes the first polarizer. A layer 817 and a layer 818 including a second polarizer are stacked. The layer 811 including the third polarizer and the layer 812 including the fourth polarizer, which are provided on the backlight side and have different absorption coefficients of the absorption axes, are arranged so as to be parallel Nicols and provided on the viewer side. In the present invention, the layer 817 including the first polarizer and the layer 818 including the second polarizer having different absorption coefficients of the absorption axes are arranged so as to deviate from parallel Nicols. Among the layers including polarizers having different coefficients, the stacked polarizers are preferably shifted on the viewing side. As a result, slight light leakage can be prevented and the contrast ratio can be increased.

If an electronic device such as a television device or a cellular phone is manufactured using the display device of the present invention, a high-functional and high-quality electronic device capable of performing three-dimensional display can be provided.

(Embodiment 13)
With the display device formed according to the present invention, a television device (also simply referred to as a television or a television receiver) can be completed. FIG. 20 is a block diagram illustrating a main configuration of the television device. In the display panel, only the pixel portion 701 is formed as shown in FIG. 16A, and the scan line side driver circuit 703 and the signal line side driver circuit 702 are combined with a TAB method as shown in FIG. In the case of mounting by the COG method as shown in FIG. 17A, the TFT is formed as shown in FIG. 16B, and the pixel portion 701 and the scanning line side driver circuit 703 are formed on the substrate. When the signal line side driver circuit 702 is separately formed as a driver IC and formed as a driver IC, the pixel portion 701, the signal line side driver circuit 702, and the scan line side driver circuit 703 are formed on the substrate as shown in FIG. However, any form is possible.

As other external circuit configurations, on the input side of the video signal, among the signals received by the tuner 704, the video signal amplification circuit 705 that amplifies the video signal, and the signals output from the video signal amplification circuit 705 are red, green, and blue colors. And a control circuit 707 for converting the video signal into the input specifications of the driver IC. The control circuit 707 outputs signals to the scanning line side and the signal line side, respectively. In the case of digital driving, a signal dividing circuit 708 may be provided on the signal line side and an input digital signal may be divided into m pieces and supplied.

Of the signals received by the tuner 704, the audio signal is sent to the audio signal amplification circuit 709, and the output is supplied to the speaker 713 through the audio signal processing circuit 710. The control circuit 711 receives the receiving station (reception frequency) and volume control information from the input unit 712, and sends a signal to the tuner 704 and the audio signal processing circuit 710.

As shown in FIGS. 21A, 21B, and 21C, these liquid crystal display modules can be incorporated into a housing to complete a television device. When a liquid crystal display module as shown in FIGS. 18A and 18B is used, a liquid crystal television device can be completed. In addition, when a display device having a three-dimensional display function as in Embodiment Mode 11 is used, a television device capable of performing three-dimensional display can be manufactured. A main screen 2003 is formed by the display module, and a speaker portion 2009, operation switches, and the like are provided as other accessory equipment. Thus, a television device can be completed according to the present invention.

A display panel 2002 is incorporated in a housing 2001, and general television broadcasting is received by a receiver 2005, and connected to a wired or wireless communication network via a modem 2004 (one direction (from a sender to a receiver)). ) Or bi-directional (between the sender and the receiver, or between the receivers). The television device can be operated by a switch incorporated in the housing or a separate remote control device 2006, and the remote control device 2006 also includes a display unit 2007 for displaying information to be output. good.

In addition, the television device may have a configuration in which a sub screen 2008 is formed using the second display panel in addition to the main screen 2003 to display channels, volume, and the like. In this configuration, the main screen 2003 and the sub-screen 2008 can be formed using the liquid crystal display panel of the present invention, the main screen 2003 is formed using an EL display panel with an excellent viewing angle, and the sub-screen has low power consumption. It may be formed of a liquid crystal display panel that can be displayed with In order to prioritize the reduction in power consumption, the main screen 2003 may be formed using a liquid crystal display panel, the sub screen may be formed using an EL display panel, and the sub screen may blink. When the present invention is used, a highly reliable display device can be obtained even when such a large substrate is used and a large number of TFTs and electronic components are used.

FIG. 21B illustrates a television device having a large display portion of 20 to 80 inches, for example, which includes a housing 2010, a keyboard portion 2012 that is an operation portion, a display portion 2011, a speaker portion 2013, and the like. The present invention is applied to manufacture of the display portion 2011. The display portion in FIG. 21B is a television device having a curved display portion because a bendable substance is used. Since the shape of the display portion can be freely designed as described above, a television device having a desired shape can be manufactured.

FIG. 21C illustrates a television device having a large display portion of 20 to 80 inches, for example, which includes a housing 2030, a display portion 2031, a remote control device 2032 that is an operation portion, a speaker portion 2033, and the like. The present invention is applied to manufacturing the display portion 2031. The television device in FIG. 21B is a wall-hanging type and does not require a large installation space.

Further, since the birefringence of the liquid crystal changes depending on the temperature, the polarization state of the light passing through the liquid crystal changes, and the light leakage from the viewing side polarizer changes. As a result, the contrast ratio varies depending on the temperature of the liquid crystal. Therefore, it is desirable to control the drive voltage so as to maintain a constant contrast ratio. In order to control the driving voltage, an element for detecting the transmittance may be arranged in the display device, and the driving voltage may be controlled based on the detection result. As an element for detecting the transmittance, a photosensor composed of an IC chip can be used. In the display device, an element for detecting temperature may be arranged, and the drive voltage may be controlled based on the detection result and the change in contrast ratio with respect to the temperature of the liquid crystal element. As an element for detecting the temperature, a temperature sensor composed of an IC chip can be used. At this time, the element for detecting the transmittance and the element for detecting the temperature are preferably arranged so as to be hidden in the housing portion of the display device.

For example, an element for detecting temperature is arranged near the liquid crystal display element of the display device of the present invention mounted on the television device shown in FIGS. It is only necessary to feed back to the circuit. Since the element for detecting the transmittance is preferably closer to the viewing side, it may be disposed on the surface of the display screen and covered with the housing. Then, the detected change in transmittance may be fed back to the circuit for controlling the drive voltage, similarly to the temperature.

Since the present invention can adjust the fine contrast ratio by shifting the absorption axis of the polarizers with different extinction coefficients, it can cope with a slight contrast ratio deviation with respect to the temperature of the liquid crystal. A contrast ratio can be obtained. Therefore, the polarizers having different extinction coefficients are stacked in layers so as to obtain an optimum contrast ratio in advance depending on the situation (indoor, outdoor, climate, etc.) in which the display device of the present invention is used. A television set or an electronic device that can display images with high image quality can be provided.

Of course, the present invention is not limited to a television device, but can be applied to various uses such as a monitor for a personal computer, an information display board in a railway station or airport, an advertisement display board in a street, etc. can do.

(Embodiment 14)
As electronic devices according to the present invention, portable information such as a television device (also simply referred to as a television or a television receiver), a digital camera, a digital video camera, a cellular phone device (also simply referred to as a cellular phone or a cellular phone), a PDA Examples include a terminal, a portable game machine, a computer monitor, a computer, an audio playback device such as a car audio, and an image playback device equipped with a recording medium such as a home game machine. A specific example will be described with reference to FIG.

A portable information terminal device illustrated in FIG. 22A includes a main body 9201, a display portion 9202, and the like. The display device of the present invention can be applied to the display portion 9202. As a result, a portable information terminal device with a high contrast ratio can be provided.

A digital video camera shown in FIG. 22B includes a display portion 9701, a display portion 9702, and the like. The display device of the present invention can be applied to the display portion 9701. As a result, a digital video camera with a high contrast ratio can be provided.

A cellular phone shown in FIG. 22C includes a main body 9101, a display portion 9102, and the like. The display device of the present invention can be applied to the display portion 9102. As a result, a mobile phone with a high contrast ratio can be provided.

A portable television device shown in FIG. 22D includes a main body 9301, a display portion 9302, and the like. The display device of the present invention can be applied to the display portion 9302. As a result, a portable television device with a high contrast ratio can be provided. In addition, the present invention can be applied to a wide variety of television devices, from a small one mounted on a portable terminal such as a cellular phone to a medium-sized one that can be carried and a large one (for example, 40 inches or more). The display device can be applied.

A portable computer shown in FIG. 22E includes a main body 9401, a display portion 9402, and the like. The display device of the present invention can be applied to the display portion 9402. As a result, a portable computer with a high contrast ratio can be provided.

As described above, the display device of the present invention can provide an electronic device with a high contrast ratio.

In this example, when a TN mode transmissive liquid crystal display device is assumed, polarizers having different extinction coefficients of absorption axes are stacked, and the polarizer closest to the viewing side is crossed with the polarizer on the backlight side. The result of optical calculation when shifted from Nicol will be described. The contrast ratio is the ratio of white transmittance (also referred to as white transmittance) to black transmittance (also referred to as black transmittance) (white transmittance / black transmittance). The contrast ratio was calculated by calculating the ratio and the transmittance during white display.

For the calculation in this example, an optical calculation simulator LCD MASTER (manufactured by Shintech Co., Ltd.) for liquid crystal was used. When calculating the transmittance with an LCD MASTER, a 2 × 2 matrix optical calculation algorithm that does not take into account multiple interference between elements was used, and the set wavelength was calculated in the range of 380 nm to 780 nm.

As shown in FIG. 32, the optical arrangement of the optical calculation object is, in order from the backlight, polarizer 1, polarizer 2, retardation plate B2, retardation plate A2, glass substrate, liquid crystal, glass substrate, retardation plate A1, The retardation plate B1, the polarizer 2, and the polarizer 1 are laminated. In this embodiment, two phase difference plates (phase difference plate A1, phase difference plate B1, phase difference plate A2, and phase difference plate B2) are arranged on the upper and lower sides for the purpose of wide viewing angle in TN mode. The polarizer 1 and the polarizer 2 on the backlight side are polarizing plates having different extinction coefficients, and both of the angles of the absorption axes are 135 degrees and are in a parallel Nicol arrangement. The polarizer 2 on the viewing side and the polarizer 1 are polarizing plates having different extinction coefficients, the angle of the absorption axis of the polarizer 2 is 45 degrees, and the crossed Nicols arrangement with the polarizer 1 on the backlight side. It has become. First, in order to obtain the absorption axis angle of the viewing side polarizer 1 with the highest contrast ratio, the contrast ratio when the angle of the absorption axis of the viewing side polarizer 1 is rotated from 30 degrees to 50 degrees is calculated. It was. Here, the contrast ratio is a ratio of 0V (white) transmittance and 5V (black) transmittance when the voltage applied to the liquid crystal is 0V and 5V (0V transmittance / 5V transmittance). The calculation in this example is a calculation result in front of the display element with respect to the backlight.

Tables 1 and 2 show physical property values of the polarizer 1 and the polarizer 2. Both polarizers had a thickness of 30 μm. Further, the birefringence values of the liquid crystal are shown in Table 3, the other physical property values and the alignment state of the liquid crystal are shown in Table 4, the physical property values and arrangement of the retardation plates A1 and A2 are shown in Table 5, and the retardation plate B1. Table 6 shows the physical property values and arrangement of the retardation plate B2. The retardation plates A1, A2, B1, and B2 are all retardation plates having negative uniaxiality.

FIG. 33 shows the results of the contrast ratio when the viewer-side polarizer 1 is rotated at a wavelength of 550 nm.

From FIG. 33, when the angle of the absorption axis of the viewing side polarizer 1 is 40.6 degrees, the contrast ratio is the highest, and it is shifted by 4.4 degrees from 45 degrees which is crossed Nicols with the polarizer on the backlight side. I understand.

Subsequently, the wavelength dependence of the contrast ratio was calculated. The structure A in FIG. 34A is the structure in FIG. 32 and is arranged such that the angle of the absorption axis of the polarizer 1 on the viewing side is 40.6 degrees. The structure B in FIG. 34B has an arrangement in which the angle of the absorption axis of the polarizer 1 on the viewing side of the structure A is 45 degrees which is a crossed Nicols arrangement with the polarizer on the backlight side. In the structure C of FIG. 34C, all the polarizers used are the polarizers 1, and the angle of the absorption axis of the polarizer 1 closest to the viewing side is 40.6 degrees. FIG. 35 shows the wavelength dispersion of the extinction coefficients of the absorption axes of the polarizer 1 and the polarizer 2. It can be seen that the extinction coefficient of the absorption axis of the polarizer 1 is large on the short wavelength side, and the extinction coefficient of the absorption axis of the polarizer 2 is large on the long wavelength side. The physical property values of the polarizers 1 and 2, the liquid crystal, the physical property values of the retardation plates A 1, A 2, B 1, and B 2, and the arrangement thereof are shown in Table 1, Table 2, Table 3, Table 4, Table 5, Table 6, and The same.

FIG. 36 shows the result of the contrast ratio of 0V transmittance and 5V transmittance in the front of the display elements of structures A, B, and C, and FIG. 37 shows an enlarged view at wavelengths from 400 nm to 600 nm. Comparing the structure A and the structure B, it can be seen that the contrast ratio is higher in the structure A in which the polarizing plates are shifted and laminated in a region other than the long wavelength region of 690 nm or more. From this, it can be seen that high contrast can be achieved by laminating the polarizing plates.

Further, when comparing the structure A and the structure C in which the polarizing plates are laminated while being shifted, the structure A in which the polarizers having different extinction coefficients of the absorption axes are laminated has higher contrast in the long wavelength region. From FIG. 35, the structure A in which the polarizer 2 having the extinction coefficient of the polarizer 1 smaller than that of the polarizer 2 in the long wavelength region and the polarizer 2 having a large extinction coefficient in the long wavelength region is stacked is longer in the long wavelength region. Since the transmittance at the time of black display (5 V) is dark, the contrast ratio can be increased.

From the above results, it is possible to obtain a high contrast ratio by laminating polarizers having different extinction coefficients of absorption axes and shifting the viewing-side polarizer from the crossed Nicols with respect to the backlight-side polarizer.

It is sectional drawing and the perspective view which showed the display apparatus of this invention. It is sectional drawing and the perspective view which showed the display apparatus of this invention. It is sectional drawing and the perspective view which showed the display apparatus of this invention. It is sectional drawing and the perspective view which showed the display apparatus of this invention. It is the figure which showed the display apparatus of this invention. It is the figure which showed the display apparatus of this invention. It is sectional drawing and the perspective view which showed the display apparatus of this invention. It is sectional drawing and the perspective view which showed the display apparatus of this invention. It is sectional drawing and the perspective view which showed the display apparatus of this invention. It is sectional drawing and the perspective view which showed the display apparatus of this invention. It is sectional drawing and the perspective view which showed the display apparatus of this invention. It is sectional drawing and the perspective view which showed the display apparatus of this invention. It is sectional drawing which showed the structure of the layer containing the polarizer of this invention. It is the top view and sectional drawing which showed the display apparatus of this invention. It is sectional drawing which showed the display apparatus of this invention. It is the top view which showed the display apparatus of this invention. It is the top view which showed the display apparatus of this invention. It is sectional drawing which showed the display apparatus of this invention. It is sectional drawing which showed the irradiation means which the display apparatus of this invention has. It is a block diagram which shows the main structures of the electronic device with which this invention is applied. It is the figure which showed the electronic device of this invention. It is the figure which showed the electronic device of this invention. It is sectional drawing which showed the display apparatus of this invention. It is the block diagram which showed the display apparatus of this invention. It is the top view which showed the display apparatus of this invention. It is the top view which showed the display apparatus of this invention. It is sectional drawing which showed the liquid crystal mode of this invention. It is sectional drawing which showed the liquid crystal mode of this invention. It is sectional drawing which showed the liquid crystal mode of this invention. It is the top view and sectional drawing which showed the display apparatus of this invention. It is sectional drawing and the perspective view which showed the display apparatus of this invention. 3 is a graph showing experimental conditions of Example 1. 2 is a graph showing experimental results of Example 1. FIG. 3 is a graph showing experimental conditions of Example 1. 2 is a graph showing experimental results of Example 1. FIG. 2 is a graph showing experimental results of Example 1. FIG. 2 is a graph showing experimental results of Example 1. FIG.

Claims (2)

A first substrate;
A second substrate;
A display element sandwiched between the first substrate and the second substrate;
A first layer including a polarizer laminated on at least three or more layers outside the first substrate;
A second layer including a laminated polarizer on the outside of the second substrate,
The plurality of polarizers of the first layer have different extinction coefficients with respect to the absorption axis,
The polarizers of the second layer have different extinction coefficients with respect to the absorption axis,
In at least two polarizers of the plurality of polarizers of the first layer, arranged so that the absorption axis of each other is not parallel Nicol ,
The plurality of polarizers of the second layer are arranged so that their absorption axes are parallel Nicols,
The plurality of polarizers included in the first layer include at least a first polarizer and a second polarizer stacked in order from the first substrate side,
The arrangement of the first polarizer is closest to the first substrate among the plurality of polarizers of the first layer,
The display device, wherein the first polarizer and the plurality of polarizers of the second layer are arranged so that their absorption axes are crossed Nicols. In claim 1 ,
The display device, wherein the plurality of polarizers included in the first layer are arranged such that their absorption axes deviate from parallel Nicols by -15 degrees or more and 5 degrees or less.

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