JP2007233361A - Display device - Google Patents

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JP2007233361A
JP2007233361A JP2007016980A JP2007016980A JP2007233361A JP 2007233361 A JP2007233361 A JP 2007233361A JP 2007016980 A JP2007016980 A JP 2007016980A JP 2007016980 A JP2007016980 A JP 2007016980A JP 2007233361 A JP2007233361 A JP 2007233361A
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substrate
polarizing plate
light
polarizing
display device
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JP2007233361A5 (en
Inventor
Yuji Egi
Tetsuji Ishitani
Takeshi Nishi
勇司 恵木
哲二 石谷
毅 西
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Semiconductor Energy Lab Co Ltd
株式会社半導体エネルギー研究所
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Abstract

An object of the present invention is to provide a display device in which the contrast ratio is increased by a simple method. Another object is to produce a display device having such a high contrast ratio at low cost.
A first substrate, a second substrate, a layer having a display element sandwiched between the first substrate and the second substrate, and the first substrate or the second substrate. Laminated polarizers, and the laminated polarizers are arranged so that their respective absorption axes are parallel Nicols and have different extinction coefficients or extinctions. The present invention relates to display devices having different coefficient wavelength distributions.
[Selection] Figure 5

Description

  The present invention relates to a configuration of a display device for increasing a contrast ratio.

  Development of a so-called flat panel display, which is much thinner and lighter than conventional CRTs, is underway. Flat panel displays are competing with liquid crystal display devices with liquid crystal elements as display elements, display devices with self-luminous elements, FED (field emission display) using electron sources, etc. Therefore, low power consumption and high contrast are required.

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

  For example, in order to increase the contrast ratio, a first polarizing plate is provided on the outside of the substrate on the viewing side of the liquid crystal cell, and a second polarizing plate is provided on the outside of the substrate opposite to the viewing side. When the light from the auxiliary light source is polarized through the second polarizing plate and passed through the liquid crystal cell, a configuration is proposed in which a third polarizing plate is provided to increase the degree of polarization (see Patent Document 1). As a result, it is possible to improve display non-uniformity and contrast ratio caused by insufficient polarization degree and polarization degree distribution of the polarizing plate.

  Further, the contrast ratio has a problem that viewing angle dependency occurs. The cause of the viewing angle dependency is that there is optical anisotropy in the major axis direction and minor axis direction of the liquid crystal molecules. Due to optical anisotropy, the appearance of liquid crystal molecules when the liquid crystal display device is viewed from the front is different from the appearance when viewed from an oblique direction. Therefore, the luminance during white display and the luminance during black display vary depending on the viewing angle, and the viewing angle dependency occurs in the contrast ratio.

  In order to improve the viewing angle dependency of the contrast ratio, a configuration in which a retardation film is inserted has been proposed. For example, in the vertical alignment mode (VA mode), the viewing angle dependency is improved by placing biaxial retardation films having different refractive indexes in three directions so as to sandwich the liquid crystal layer ( Non-patent document 1).

  In addition, in the twisted nematic mode (TN mode), a configuration using a laminate of wide view (WV) films in which a discotic liquid crystal compound is hybrid-aligned is proposed (see Patent Document 5).

  In addition, in order to solve the problem of deterioration of the polarizing plate in the projection type liquid crystal display device, a configuration is proposed in which two or more linear polarizing plates are laminated with their absorption axes coincided to reduce the deterioration in display quality. (See Patent Document 6).

  As a flat panel display similar to a liquid crystal display device, there is a display device having an electroluminescence element. Since the electroluminescence element is a self-luminous element and does not require light irradiation means such as a backlight, the display device can be thinned. Furthermore, a display device having an electroluminescence element has advantages such as a faster response speed and less viewing angle dependency than a liquid crystal display device.

  A configuration in which a polarizing plate and a circularly polarizing plate are provided is also proposed for a display device having such an electroluminescence element (see Patent Documents 2 and 3).

As a structure of a display device having an electroluminescence element, light emitted from a light emitting element sandwiched between light-transmitting substrates can observe both light on the anode substrate side and light on the cathode substrate side. Has been proposed (see Patent Document 4).

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. Further, when the polarizing plates are laminated, the contrast ratio is improved, but a slight light leak cannot be suppressed. This is because the wavelength dependency of the absorption characteristics is not constant, and the absorption characteristics in a specific wavelength region are lower than those in other wavelength regions, that is, the absorption property is difficult to absorb only in that wavelength region. by. When using a polarizing plate, it is common to use the same type, so even if it is used repeatedly to improve contrast, a wavelength region that hardly absorbs light exists as it is. This causes a slight light leak. This light leakage hindered further improvement in contrast ratio.
Optimum Compensation Modes for TN and VA LCDs SID98 DIGEST P.M. 315-318 International Publication No. 00/34821 Japanese Patent No. 2761453 Japanese Patent No. 3174367 Japanese Patent Laid-Open No. 10-255976 Japanese Patent No. 3315476 JP 2003-172819 A

  However, the demand for increasing the contrast ratio does not stop, and research has been made on improving contrast in display devices.

  For example, the black luminance of a liquid crystal display device is higher than the black luminance in a non-light emitting state of a light emitting element such as a plasma display panel (PDP) or an electroluminescence (EL) panel, resulting in a low contrast ratio. There is a problem, and the demand for improving the contrast ratio is high.

  Moreover, the request | requirement which raises a contrast ratio is calculated | required not only for a liquid crystal display device but for the display device which has an electroluminescent element.

  Therefore, an object of the present invention is to improve the contrast ratio of a display device. It is another object of the present invention to provide a display device having a wide viewing angle.

  Another object is to produce such a high-performance display device at low cost.

  In view of the above problems, the present invention is characterized in that a plurality of linear polarizers are provided on one substrate. The plurality of polarizers may be formed by stacking a polarizing plate including one polarizing film, or may be formed by stacking a plurality of polarizing films in one polarizing plate. Alternatively, a polarizing plate including a plurality of polarizing films may be stacked.

  Each of the plurality of linear polarizers provided on one substrate has a different extinction coefficient of the absorption axis. Or each of the some linear polarizer provided on one board | substrate may differ in the wavelength distribution of an extinction coefficient. Thereby, even if the wavelength dependence of the absorption characteristic of each polarizer is not constant, the wavelength region to be absorbed can be expanded by overlapping the polarizers having different extinction coefficients of the absorption axes. That is, even if one of the stacked polarizers has a characteristic that it is difficult to absorb only light in a specific wavelength region, another polarizer can absorb light in that wavelength region. Light in a wide range of wavelengths can be absorbed.

  In this specification, a polarizer obtained by laminating a plurality of polarizers, a polarizing film obtained by laminating a plurality of polarizing films, and a polarizing plate obtained by laminating a plurality of polarizing plates. Call it.

  The plurality of polarizers are arranged so that their absorption axes are parallel Nicols.

  Parallel Nicol is an arrangement in which the deviation between the absorption axes of the polarizer is 0 °. On the other hand, the crossed Nicol is an arrangement in which the absorption axes of the polarizers are shifted by 90 °. Note that a transmission axis is provided so as to be orthogonal to the absorption axis of the polarizer, and crossed Nicols and parallel Nicols are similarly defined even when the transmission axes are used.

  In addition, a plurality of laminated linear polarizers having different extinction coefficients are used. Alternatively, the plurality of laminated linear polarizers may have different wavelength distributions of extinction coefficients.

  Further, a retardation plate (also referred to as a retardation film or a wavelength plate) may be provided between the laminated polarizer and the substrate.

  Of those having a polarizing plate and a retardation plate, a retardation plate using a quarter wavelength plate (also referred to as a λ / 4 plate) is called a circular polarizing plate, and thus laminated on a quarter wavelength plate. As a configuration for disposing the polarizing plate, a laminate of a circularly polarizing plate and a polarizing plate may be used.

  The polarizer provided on one substrate and the quarter wavelength plate are arranged so as to be shifted by 45 °. Specifically, when the angle of the absorption axis of the polarizer is 0 ° (when the angle of the transmission axis is 90 °), the angle of the slow axis of the quarter wave plate is 45 ° or 135 °. Deploy.

  In the present specification, it is preferable that the absorption axis of the polarizer provided on one substrate and the slow axis of the quarter-wave plate are arranged so as to be shifted by 45 °, but similar effects can be exhibited. In this case, it may be slightly deviated from 45 °.

  The present invention relates to the following display device configuration.

  The present invention includes a first substrate, a second substrate, a layer having a display element sandwiched between the first substrate and the second substrate, and the first substrate or the second substrate. A laminated polarizer on the outside, wherein the laminated polarizers are arranged such that their absorption axes are parallel Nicols, and have different extinction coefficients. The present invention relates to a display device. Alternatively, the plurality of laminated linear polarizers may have different wavelength distributions of extinction coefficients.

  In the present invention, a first substrate, a second substrate, a layer having a display element sandwiched between the first substrate and the second substrate, and a layer outside the first substrate are stacked. And polarizers stacked on the outside of the second substrate, and the polarizers stacked on the outside of the first substrate have their respective absorption axes in parallel Nicols. And the polarizers laminated on the outside of the second substrate are arranged so that their absorption axes are parallel Nicols, and each has an extinction coefficient. Differently, the absorption axis of the polarizer laminated on the outside of the first substrate and the absorption axis of the polarizer laminated on the outside of the second substrate are arranged so as to be crossed Nicols. It is related with the display apparatus. Alternatively, the laminated polarizers may have different wavelength distributions of extinction coefficients.

  In the present invention, a first substrate, a second substrate, a layer having a display element sandwiched between the first substrate and the second substrate, and a layer outside the first substrate are stacked. And polarizers stacked on the outside of the second substrate, and the polarizers stacked on the outside of the first substrate have their respective absorption axes in parallel Nicols. And the polarizers laminated on the outside of the second substrate are arranged so that their absorption axes are parallel Nicols, and each has an extinction coefficient. Unlikely, the absorption axis of the polarizer laminated on the outside of the first substrate and the absorption axis of the polarizer laminated on the outside of the second substrate are arranged to be parallel Nicols. It is related with the display apparatus. Alternatively, the laminated polarizers may have different wavelength distributions of extinction coefficients.

  The present invention includes a first substrate, a second substrate, a layer having a display element sandwiched between the first substrate and the second substrate, and the first substrate or the second substrate. The polarizer includes a laminated polarizer, the first substrate or the second substrate, and a retardation plate between the laminated polarizers, and the laminated polarizer is In addition, the present invention relates to a display device characterized in that the respective absorption axes are arranged in parallel Nicols and the extinction coefficients are different from each other. Alternatively, the laminated polarizers may have different wavelength distributions of extinction coefficients.

  In the present invention, a first substrate, a second substrate, a layer having a display element sandwiched between the first substrate and the second substrate, and a layer outside the first substrate are stacked. A first phase difference between the polarizer stacked on the outside of the second substrate, the polarizer stacked on the outside of the first substrate, and the first substrate. A second retardation plate between the plate, the second substrate, and a polarizer laminated outside the second substrate, and laminated outside the first substrate. The polarizers are arranged so that their respective absorption axes are parallel Nicols and have different extinction coefficients, and the polarizers stacked outside the second substrate have their respective absorption axes. Polarizers arranged so as to be parallel Nicols and having different extinction coefficients and stacked on the outside of the first substrate The absorption axis, said second absorption axis of the polarizer laminated on the outer side of the substrate is intended to a display apparatus characterized by being arranged so as to be in a cross nicol state. Alternatively, the laminated polarizers may have different wavelength distributions of extinction coefficients.

  In the present invention, a first substrate, a second substrate, a layer having a display element sandwiched between the first substrate and the second substrate, and a layer outside the first substrate are stacked. A first phase difference between the polarizer stacked on the outside of the second substrate, the polarizer stacked on the outside of the first substrate, and the first substrate. A second retardation plate between the plate, the second substrate, and a polarizer laminated outside the second substrate, and laminated outside the first substrate. The polarizers are arranged so that their respective absorption axes are parallel Nicols and have different extinction coefficients, and the polarizers stacked outside the second substrate have their respective absorption axes. Polarizers arranged so as to be parallel Nicols and having different extinction coefficients and stacked on the outside of the first substrate The absorption axis, said second absorption axis of the polarizer laminated on the outer side of the substrate is intended to a display apparatus characterized by being arranged so as to be in a parallel nicol state. Alternatively, the laminated polarizers may have different wavelength distributions of extinction coefficients.

  In the present invention, the display element is a liquid crystal element.

  In the present invention, the display element is an electroluminescence element.

  According to one aspect of the display device of the present invention, a display element sandwiched between a first light-transmitting substrate and a second light-transmitting substrate, the first light-transmitting substrate, The polarizing plates laminated on the outer side of the translucent substrate 2 have different extinction coefficients with respect to each other's absorption axis, and the laminated polarizing plates have mutually parallel absorption axes. Arranged to be Nicol. Alternatively, the laminated polarizing plates may have different wavelength distributions of extinction coefficients.

  One display device of the present invention includes a display element sandwiched between a first light-transmitting substrate and a second light-transmitting substrate, which are disposed to face each other, and an outer side of the first light-transmitting substrate. A first laminated polarizing plate and a second laminated polarizing plate having a first laminated polarizing plate and a second laminated polarizing plate outside the second light-transmitting substrate Are different from each other in the extinction coefficient with respect to each other's absorption axis, and the first laminated polarizing plate and the second laminated polarizing plate have mutually different absorption axes. Are arranged in parallel Nicols. Alternatively, the laminated polarizing plates may have different wavelength distributions of extinction coefficients.

  One display device of the present invention includes a display element sandwiched between a first light-transmitting substrate and a second light-transmitting substrate, which are disposed to face each other, and an outer side of the first light-transmitting substrate. A first laminated polarizing plate and a second laminated polarizing plate having a first laminated polarizing plate and a second laminated polarizing plate outside the second light-transmitting substrate Are different from each other in the extinction coefficient with respect to each other's absorption axis, and the first laminated polarizing plate and the second laminated polarizing plate have mutually different absorption axes. Are arranged in parallel Nicols. Alternatively, the laminated polarizing plates may have different wavelength distributions of extinction coefficients.

  One display device of the present invention includes a display element sandwiched between a first light-transmitting substrate and a second light-transmitting substrate, which are disposed to face each other, and an outer side of the first light-transmitting substrate. A first retardation plate, a second retardation plate outside the second translucent substrate, a first laminated polarizing plate outside the first retardation plate, and a second retardation A second laminated polarizing plate on the outside of the plate, and the first laminated polarizing plate and the second laminated polarizing plate are extinguished with respect to each other's absorption axis in each of the laminated polarizing plates. The coefficients are different, and the first laminated polarizing plate and the second laminated polarizing plate are arranged so that their absorption axes are parallel Nicols in the laminated polarizing plates. Alternatively, the laminated polarizers may have different wavelength distributions of extinction coefficients.

  According to one embodiment of the present invention, a display element sandwiched between a first light-transmitting substrate and a second light-transmitting substrate, the first light-transmitting substrate, And a polarizing plate laminated on the outer side of the light-transmitting substrate, and the laminated polarizing plates are arranged so that their absorption axes are parallel Nicols.

  Another embodiment of the present invention includes a display element sandwiched between a first light-transmitting substrate and a second light-transmitting substrate, facing each other, an outside of the first light-transmitting substrate, and a first Each of the polarizing plates laminated on the outer sides of the two light-transmitting substrates, the laminated polarizing plates are arranged so that their absorption axes are parallel Nicols, and are arranged on the first light-transmitting substrate. The display device is characterized in that the absorption axis of the provided polarizing plate and the absorption axis of the polarizing plate provided on the second light-transmitting substrate are arranged to be crossed Nicols.

  Another embodiment of the present invention includes a display element sandwiched between a first light-transmitting substrate and a second light-transmitting substrate that are disposed to face each other, and the first light-transmitting substrate or the second light-transmitting substrate. Polarized light having a color filter provided inside the translucent substrate, and a polarizing plate laminated on the outside of the first translucent substrate and on the outside of the second translucent substrate, respectively. The plates are arranged so that their absorption axes are parallel Nicols, and the absorption axis of the polarizing plate provided on the first light-transmitting substrate and the polarizing plate provided on the second light-transmitting substrate The absorption axis is a display device that is arranged to be crossed Nicols.

  Another embodiment of the present invention includes a display element sandwiched between a first light-transmitting substrate and a second light-transmitting substrate, facing each other, an outside of the first light-transmitting substrate, and a first Each of the polarizing plates laminated on the outer sides of the two light-transmitting substrates, the laminated polarizing plates are arranged so that their absorption axes are parallel Nicols, and are arranged on the first light-transmitting substrate. When the absorption axis of the provided polarizing plate and the absorption axis of the polarizing plate provided on the second light-transmitting substrate are arranged to be crossed Nicols, and the laminated polarizing plates are arranged in parallel Nicols The transmittance change is larger than the transmittance change when the laminated polarizing plates are arranged in crossed Nicols.

  Another embodiment of the present invention includes a display element sandwiched between a first light-transmitting substrate and a second light-transmitting substrate, facing each other, an outside of the first light-transmitting substrate, and a first Each of the polarizing plates laminated on the outer sides of the two light-transmitting substrates, the laminated polarizing plates are arranged so that their absorption axes are parallel Nicols, and are arranged on the first light-transmitting substrate. When the absorption axis of the provided polarizing plate and the absorption axis of the polarizing plate provided on the second light-transmitting substrate are arranged to be crossed Nicols, and the laminated polarizing plates are arranged in parallel Nicols The ratio between the transmittance when the stacked polarizing plates are arranged in crossed Nicols is the ratio between the transmittance when the polarizing plates are arranged in parallel Nicols as a single layer and the polarizing plate is crossed as a single layer. Display device characterized by being higher than the ratio of transmittance when placed in Nicol It is.

  In the present invention, the stacked polarizing plates are provided such that the first polarizing plate and the second polarizing plate are in contact with each other.

  In the present invention, the display element is a liquid crystal element.

  In one embodiment of the present invention, the first light-transmitting substrate and the second light-transmitting substrate are disposed so as to face each other, and sandwiched between the first light-transmitting substrate and the second light-transmitting substrate. A display element, a retardation film and a laminated polarizing plate, which are sequentially arranged on the outside of the first light-transmitting substrate or the outside of the second light-transmitting substrate, and the polarizing plate, The laminated polarizing plates are liquid crystal display devices that are arranged so that their absorption axes are parallel Nicols.

  In another embodiment of the present invention, the first light-transmitting substrate and the second light-transmitting substrate are disposed so as to face each other, and sandwiched between the first light-transmitting substrate and the second light-transmitting substrate. The display element, the retardation film, the laminated polarizing plate, and the second light-transmitting substrate, which are sequentially disposed on the outside of the first light-transmitting substrate, A liquid crystal display device having a retardation film and a polarizing plate, wherein the laminated polarizing plates are arranged so that their absorption axes are parallel Nicols.

  In another embodiment of the present invention, the first light-transmitting substrate and the second light-transmitting substrate are disposed so as to face each other, and sandwiched between the first light-transmitting substrate and the second light-transmitting substrate. A display element, a retardation film and a laminated polarizing plate, which are sequentially arranged on the outside of the first light-transmitting substrate and the outside of the second light-transmitting substrate, respectively, The laminated polarizing plates are arranged such that their absorption axes are parallel Nicols, and the polarizing axes of the polarizing plates provided on the first light-transmitting substrate and the second light-transmitting substrate The liquid crystal display device is characterized in that it is arranged so as to be crossed Nicols with respect to the absorption axis of the polarizing plate provided in the plate.

  In another embodiment of the present invention, the first light-transmitting substrate and the second light-transmitting substrate are disposed so as to face each other, and sandwiched between the first light-transmitting substrate and the second light-transmitting substrate. A display element, a color filter provided inside the first light-transmitting substrate or the second light-transmitting substrate, an outer side of the first light-transmitting substrate, and the second light-transmitting substrate A retardation film and a laminated polarizing plate, which are sequentially arranged on the outer side of the translucent substrate, each have a laminated polarizing plate, and the laminated polarizing plates are arranged so that their absorption axes are parallel Nicols. And the absorption axis of the polarizing plate provided on the first light-transmitting substrate and the absorption axis of the polarizing plate provided on the second light-transmitting substrate are arranged so as to be crossed Nicols. This is a liquid crystal display device.

  In the present invention, the laminated polarizing plate is preferably composed of two polarizing plates.

  In the present invention, the retardation film is a film in which liquid crystals are hybrid-aligned, a film in which liquid crystals are twisted and aligned, a uniaxial retardation film, or a biaxial retardation film.

  In the present invention, the first light-transmitting substrate includes a first electrode, the second light-transmitting substrate includes a second electrode, and the display element includes the first electrode and the second electrode. The liquid crystal element performs white display when a voltage is applied between the second electrodes and performs black display when no voltage is applied between the first electrode and the second electrode.

  In the present invention, the first light-transmitting substrate includes a first electrode, the second light-transmitting substrate includes a second electrode, and the display element includes the first electrode and the second electrode. The liquid crystal element performs white display when a voltage is not applied between the second electrodes and performs black display when a voltage is applied between the first electrode and the second electrode.

  The present invention includes a first substrate, a second substrate facing the first substrate, a liquid crystal provided between the first and second substrates, the first substrate and the second one A reflective material comprising: a reflective material provided on the substrate; and a circularly polarizing plate disposed outside the other of the first substrate and the second substrate and having a retardation plate and a laminated linearly polarizing plate. The present invention relates to a liquid crystal display device.

  In the present invention, the transmission axes of the laminated linearly polarizing plates are all arranged in parallel Nicols.

  In the present invention, the retardation plate is a uniaxial retardation plate or a biaxial retardation plate.

  According to another aspect of the display device of the present invention, the first light-transmitting substrate and the second light-transmitting substrate are disposed so as to face each other, and the first light-transmitting substrate is provided between the opposed substrates. A light emitting element capable of emitting light emitted in both directions of the substrate and the second light transmissive substrate, a laminated first linearly polarizing plate disposed outside the first light transmissive substrate, and It is set as the structure which has the laminated | stacked 2nd linearly-polarizing plate arrange | positioned on the outer side of the 2nd translucent board | substrate.

  In another display device of the present invention, the first light-transmitting substrate and the second light-transmitting substrate are disposed so as to face each other, and are provided between the opposed substrates. A light emitting element capable of emitting light emitted in both directions of the translucent substrate and the second translucent substrate, and a stacked first linearly polarizing plate disposed outside the first translucent substrate And a laminated second linearly polarizing plate disposed outside the second translucent substrate, and the transmission axes of the laminated first linearly polarizing plates are all parallel Nicols. The transmission axes of the laminated second linearly polarizing plates are arranged so as to be parallel Nicols.

  In another display device of the present invention, the first light-transmitting substrate and the second light-transmitting substrate are disposed so as to face each other, and are provided between the opposed substrates. A light-emitting element capable of emitting light emitted in both directions of the light-transmitting substrate and the second light-transmitting substrate, and a stacked first linearly polarized light disposed outside the first light-transmitting substrate And a laminated second linearly polarizing plate disposed outside the second translucent substrate, and the transmission axes of the laminated first linearly polarizing plates are all parallel Nicols. The transmission axes of the stacked second linear polarizing plates are all arranged in parallel Nicols, the transmission axes of the stacked first linear polarizing plates, and the stacked The transmission axis of the second linear polarizing plate is arranged to be crossed Nicols.

  The first translucent substrate and the second translucent substrate are disposed so that the first translucent substrate and the second translucent substrate are opposed to each other, and are provided between the opposed substrates. A light emitting element capable of emitting light emitted in both directions, a laminated first linearly polarizing plate disposed outside the first light transmissive substrate, and an outside of the second light transmissive substrate. And the second linearly polarizing plate is arranged so that the transmission axes of the laminated first linearly polarizing plates are all parallel Nicols, and the laminated first linearly polarized light The transmission axis of the plate and the transmission axis of the second linear polarizing plate are arranged to be crossed Nicols.

  Moreover, in the structure of this invention, the structure by which the said polarizing plate was provided in contact with the said laminated | stacked polarizing plate may be sufficient.

  The first light-transmitting substrate and the second light-transmitting substrate are disposed so as to face each other, and are provided between the opposed substrates. A light-emitting element capable of emitting light emitted in both directions, a first circularly polarizing plate disposed outside the first light-transmitting substrate and having a stacked first linearly polarizing plate, and a second transparent plate And a second circularly polarizing plate having a stacked second linearly polarizing plate disposed outside the optical substrate.

  The first light-transmitting substrate and the second light-transmitting substrate are disposed so as to face each other, and are provided between the opposed substrates. A light-emitting element capable of emitting light emitted in both directions, a first circularly polarizing plate disposed outside the first light-transmitting substrate and having a stacked first linearly polarizing plate, and a second transparent plate A second circularly polarizing plate disposed on the outside of the optical substrate and having a laminated second linearly polarizing plate, and the transmission axes of the laminated first linearly polarizing plates are all parallel Nicols The transmission axes of the laminated second linear polarizing plates are arranged in parallel Nicols, and the transmission axes of the laminated first linear polarizing plates and the laminated second straight lines The display device is characterized in that the transmission axis of the polarizing plate is arranged in parallel Nicols.

  The first light-transmitting substrate and the second light-transmitting substrate are disposed so as to face each other, and are provided between the opposed substrates. A light emitting element capable of emitting light emitted in both directions, a stacked first linear polarizing plate disposed outside the first light transmissive substrate, and disposed outside the second light transmissive substrate. In addition, the laminated second linearly polarizing plate, the first translucent substrate, the first retardation plate provided between the first linearly polarizing plate, and the second translucent substrate And a second retardation plate provided between the second linear polarizing plate, and the transmission axes of the laminated first linear polarizing plates are all arranged in parallel Nicols, The transmission axes of the laminated second linear polarizing plates are all arranged in parallel Nicols, and the transmission axes of the laminated first linear polarizing plates and the laminated first linear polarizing plates are arranged. The transmission axis of the linear polarizer is arranged so as to be parallel Nicol, the slow axis of the first retardation plate is arranged to be shifted by 45 ° with respect to the transmission axis of the first linear polarizer, The display device is characterized in that the slow axis of the second retardation plate is shifted by 45 ° with respect to the transmission axis of the second linearly polarizing plate.

  The first light-transmitting substrate and the second light-transmitting substrate are disposed so as to face each other, and are provided between the opposed substrates. A light emitting element capable of emitting light emitted in both directions, a stacked first linear polarizing plate disposed outside the first light transmissive substrate, and disposed outside the second light transmissive substrate. In addition, the second linearly polarizing plate, the first translucent substrate, the first retardation plate provided between the first linearly polarizing plate, the second translucent substrate, And a second retardation plate provided between the two linear polarizing plates, and the transmission axes of the laminated first linear polarizing plates are all arranged in parallel Nicols and laminated. The transmission axis of the first linearly polarizing plate and the transmission axis of the second linearly polarizing plate are arranged so as to be parallel Nicols, and the first linearly polarizing plate has a first axis with respect to the transmission axis of the first linearly polarizing plate. The retardation plate is arranged so that the slow axis of the retardation plate is shifted by 45 °, and the slow axis of the second retardation plate is arranged by 45 ° with respect to the transmission axis of the second linearly polarizing plate. It is a display device.

  The first light-transmitting substrate and the second light-transmitting substrate are disposed so as to face each other, and are provided between the opposed substrates. A light-emitting element capable of emitting light emitted in both directions, a first circularly polarizing plate disposed outside the first light-transmitting substrate and having a stacked first linearly polarizing plate, and a second transparent plate Arranged so that the transmission axes of the second circularly polarizing plate having the stacked second linearly polarizing plates and the stacked first linearly polarizing plates are all parallel Nicols arranged outside the optical substrate. The transmission axes of the laminated second linearly polarizing plates are all arranged in parallel Nicols, the transmission axis of the laminated first linearly polarizing plate and the transmission of the laminated second linearly polarizing plate A shaft is a display device that is arranged to be crossed Nicols.

  The first light-transmitting substrate and the second light-transmitting substrate are disposed so as to face each other, and are provided between the opposed substrates. A light emitting element capable of emitting light emitted in both directions, a stacked first linear polarizing plate disposed outside the first light transmissive substrate, and disposed outside the second light transmissive substrate. In addition, the laminated second linearly polarizing plate, the first translucent substrate, the first retardation plate provided between the first linearly polarizing plate, and the second translucent substrate And a second retardation plate provided between the second linear polarizing plate, and the transmission axes of the laminated first linear polarizing plates are all arranged in parallel Nicols, The transmission axes of the laminated second linear polarizing plates are all arranged in parallel Nicols, and the transmission axes of the laminated first linear polarizing plates and the laminated first linear polarizing plates are arranged. The transmission axis of the linear polarizing plate is arranged so as to be crossed Nicols, and the transmission axis of the first linear polarizing plate is arranged so as to be shifted by 45 ° from the slow axis of the first retardation plate, The second linear polarizing plate is disposed so as to be shifted from the slow axis of the second retardation plate by 45 ° with respect to the transmission axis of the second linear polarizing plate, and the second linear polarizing plate with respect to the transmission axis of the first linear polarizing plate. This is a display device characterized in that the transmission axis is arranged so as to be shifted by 90 °.

  The first light-transmitting substrate and the second light-transmitting substrate are disposed so as to face each other, and are provided between the opposed substrates. A light emitting element capable of emitting light emitted in both directions, a stacked first linear polarizing plate disposed outside the first light transmissive substrate, and disposed outside the second light transmissive substrate. In addition, the second linearly polarizing plate, the first translucent substrate, the first retardation plate provided between the first linearly polarizing plate, the second translucent substrate, And a second retardation plate provided between the two linear polarizing plates, and the transmission axes of the laminated first linear polarizing plates are all arranged in parallel Nicols and laminated. The transmission axis of the first linearly polarizing plate and the transmission axis of the second linearly polarizing plate are arranged so as to be crossed Nicols, and the first linearly polarizing plate has a first axis with respect to the transmission axis of the first linearly polarizing plate. The first phase difference plate is arranged so as to be deviated by 45 ° from the slow axis of the phase difference plate, and is arranged so as to be deviated by 45 ° from the slow axis of the second phase difference plate with respect to the transmission axis of the second linear polarizing plate. The display device is characterized in that the transmission axis of the second linear polarizing plate is arranged to be shifted by 90 ° with respect to the transmission axis of the linear polarizing plate.

  The present invention includes a first substrate, a second substrate facing the first substrate, a light emitting element provided between the first and second substrates, the first substrate, and a second substrate A circularly polarizing plate having a retardation plate and a laminated linearly polarizing plate disposed on one outer side of the substrate, and the light from the light emitting element is emitted from the first substrate and the second substrate. The present invention relates to a display device characterized by being emitted from one side.

  In the present invention, the transmission axes of the laminated linearly polarizing plates are all arranged in parallel Nicols.

  In this invention, it arrange | positions so that the slow axis of the said phase difference plate may shift | deviate 45 degrees with respect to the transmission axis of the said linearly-polarizing plate.

  In the present invention, the light-emitting element includes an electroluminescent layer formed between electrodes of a pair of electrodes, one of the pair of electrodes has reflectivity, and the other of the pair of electrodes has a light-transmitting property. It has sex.

  In the present invention, the retardation plate and the laminated linearly polarizing plates are disposed outside the translucent electrode-side substrate.

  Crossed Nicol is an arrangement in which the transmission axes of the polarizing plates are shifted by 90 °. Parallel Nicol is arranged such that the deviation between the transmission axes of the polarizing plates is 0 °. Further, an absorption axis is provided so as to be orthogonal to the transmission axis of the polarizing plate, and parallel Nicol is similarly defined even when the absorption axis is used.

  In this specification, in parallel Nicol, it is preferable that the shift between the absorption axes of the polarizers is 0 ° or 0 ° ± 10 °. It may be slightly off. In crossed Nicols, it is preferable that the absorption axes of the polarizers are shifted by 90 ° or ± 10 °. However, the above angle is assumed, but if the same effect can be exhibited, the angle is somewhat It may be shifted.

  In the present invention, the display element is a light emitting element. As a light emitting element, there are an element using electroluminescence (electroluminescence element), an element using plasma, and an element using field emission. An electroluminescent element (also referred to as an “EL element” in this specification) can be distinguished from an organic EL element or an inorganic EL element depending on a material to which the element is applied. A display device having such a light-emitting element is also referred to as a light-emitting device.

  In the present invention, the laminated polarizers have different extinction coefficients. Alternatively, the laminated polarizers may have different wavelength distributions of extinction coefficients.

  Note that the present invention can be applied to both an active matrix display device using switching elements and a passive matrix display device in which no switching elements are formed.

  With a simple structure such as providing a plurality of polarizers, the contrast ratio of the display device can be increased. It should be noted that the wavelength dependence of the absorption characteristics can be made constant because the extinction coefficients of the respective absorption axes of a plurality of polarizers provided on one substrate are different, and by suppressing slight light leakage, The contrast ratio can be further increased.

  Further, by stacking the absorption axes of a plurality of polarizers so as to be parallel Nicols, black display can be darkened, that is, black luminance can be increased, and the contrast ratio of the display device can be increased.

  Further, according to the present invention, the contrast ratio of the display device can be increased, and at the same time, the viewing angle can be improved by the phase difference plate, thereby providing a display device having a wide viewing angle.

  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, the concept of the display device of the present invention will be described with reference to FIGS.

  1A is a cross-sectional view of a display device provided with stacked polarizers, and FIG. 1B is a perspective view of the display device.

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

  A light-transmitting substrate can be used as the first substrate 101 and the second substrate 102. As such a light-transmitting substrate, a glass substrate such as barium borosilicate glass or alumino borosilicate glass, a quartz substrate, or the like can be used. For the light-transmitting substrate, polyethylene-terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), plastic (typified by polycarbonate (PC)), and flexible synthetic materials such as acrylic. A substrate made of a resin can be applied.

  A laminated polarizer is provided on the outside of the substrate 101, that is, on the side not in contact with the display element 100. A first polarizer 103 and a second polarizer 104 are provided outside the first substrate 101.

  Next, referring to the perspective view shown in FIG. 1B, the absorption axis 151 of the first polarizer 103 and the absorption axis 152 of the second polarizer 104 are stacked so as to be parallel to each other. This parallel state is called parallel Nicol.

  The polarizers stacked in this way are arranged so as to be 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, even when the transmission axes are parallel to each other, it can be called parallel Nicol.

The extinction coefficients of the first polarizer 103 and the second polarizer 104 are different. However, in this specification, the range of the extinction coefficient of the absorption axis of the polarizer is 3.0 × 10 −4 to 3.0 × 10 −2 . The extinction coefficient of the first polarizer 103 and the extinction coefficient of the second polarizer 104 may be different within this range. Alternatively, the wavelength distribution of the extinction coefficient of the first polarizer 103 and the second polarizer 104 may be different. The same applies to the following embodiments and examples.

  1A to 1B illustrate an example in which two layers of polarizers are stacked, three or more layers may be stacked.

  By stacking so that the absorption axes of the stacked polarizers are parallel Nicols, the black display can be darkened, that is, the black luminance can be increased, and thus the contrast ratio of the display device can be increased. it can.

  Note that this embodiment can be implemented freely combining with any of the other embodiments and examples in this specification, if necessary.

[Embodiment 2]
In this embodiment, a structure of stacked polarizers will be described with reference to FIGS.

  FIG. 2A illustrates an example in which a polarizing plate having one polarizing film is stacked as an example of stacked polarizers.

  In FIG. 2A, a polarizing plate 113 and a polarizing plate 114 are linear polarizing plates, respectively, and can be formed using a known material with the following structure. For example, similarly to the polarizing plate 113 having the configuration in which the adhesive layer 131, the protective film 132, the polarizing film 133, and the protective film 132 are sequentially stacked from the substrate 111 side, the protective film 136, A polarizing plate 114 having a polarizing film 137 and a protective film 136 can be used (see FIG. 2A). As the protective films 132 and 136, TAC (triacetyl cellulose) or the like can be used. As the polarizing film 133 and the polarizing film 137, a mixed layer of PVA (polyvinyl alcohol) and a dichroic dye is formed. Dichroic pigments include iodine and dichroic organic dyes. Moreover, a polarizing plate may be called a polarizing film from the shape. Further, the upper and lower positions of the polarizing plate 113 and the polarizing plate 114 may be reversed. Further, an antiglare treatment or an antireflection treatment may be performed on the surface of the protective film 136.

  FIG. 2B shows an example in which a plurality of polarizing films are stacked on one polarizing plate as an example of stacked polarizers. In FIG. 2B, an adhesive layer 140, a protective film 142, a polarizing film (A) 143, a polarizing film (B) 144, and a polarizing plate 145 having a protective film 142 are stacked from the substrate 111 side. In addition, the polarizing film 143 and the polarizing film 144 may be turned upside down. Further, an antiglare treatment or an antireflection treatment may be performed on the surface of the protective film 142.

  Further, FIG. 2C illustrates another example in which a plurality of polarizing films are stacked over one polarizing plate. 2C illustrates a polarizing plate 149 in which an adhesive layer 141, a protective film 146, a polarizing film (A) 147, a protective film 146, a polarizing film (B) 148, and a protective film 146 are stacked from the substrate 111 side. That is, the structure in FIG. 2C is a structure in which a protective film is provided between the polarizing film and the polarizing film. Moreover, the polarizing film 147 and the polarizing film 148 may be reversed in the vertical position. Further, the surface of the protective film 146 may be subjected to antiglare treatment or antireflection treatment.

  The protective films 142 and 146 may be made of the same material as the protective film 132, and the polarizing film (A) 143, the polarizing film (B) 144, the polarizing film (A) 147, and the polarizing film (B) 148 A material similar to that of the film 133 or the polarizing film 137 may be used.

  2A to 2C show an example in which two polarizers are stacked, the number of polarizers is of course not limited to two. When three or more polarizers are stacked, three or more polarizing plates may be stacked as long as the structure shown in FIG. In the structure of FIG. 2B, the number of polarizing films provided between the protective films 142 may be increased. 2C, the protective film 146, the polarizing film (A) 147, the protective film 146, the polarizing film (B) 148, the protective film 146, the polarizing film (C), the protective film 146, and so on. In addition, a polarizing film and a protective film provided thereon may be stacked.

  Further, the stacked structures shown in FIGS. 2A to 2C may be combined. That is, for example, a polarizing plate 113 including the polarizing film 133 illustrated in FIG. 2A and a polarizing film 145 including the polarizing film 143 and the polarizing film 144 illustrated in FIG. It may be configured. Such a stacked polarizer structure may be formed by appropriately combining FIGS. 2A to 2C as necessary.

  Further, a plurality of polarizing plates 145 in FIG. 2B may be stacked in order to stack polarizers. Similarly, a structure in which a plurality of polarizing plates 149 in FIG.

If the absorption axes of the polarizers are arranged in parallel Nicols, in FIG. 2A, the absorption axes of the polarizing plate 113 and the polarizing plate 114 are parallel Nicols, that is, the polarizing film 133. And the absorption axes of the polarizing film 137 are parallel Nicols. In FIG. 2B, the absorption axes of the polarizing film 143 and the polarizing film 144 are arranged in parallel Nicols. In FIG. 2C, the absorption axes of the polarizing film 147 and the polarizing film 148 are arranged in parallel Nicols.
Even if the number of polarizing films and polarizing plates increases, the respective absorption axes are arranged in parallel Nicols.

  2A to 2C show an example in which two polarizers are stacked, an example in which three polarizers are stacked is shown in FIGS. 59A to 59B.

  FIG. 59A illustrates an example in which the polarizing plate 113 including the polarizing film 133 in FIG. 2A and the polarizing film 145 including the polarizing film 143 and the polarizing film 144 in FIG. Note that the polarizing plate 113 and the polarizing plate 145 may be upside down. Further, an antiglare treatment or an antireflection treatment may be performed on the surface of the protective film 142.

  FIG. 59B illustrates an example in which the polarizing plate 113 including the polarizing film 133 in FIG. 2A and the polarizing plate 149 including the polarizing film 147 and the polarizing film 148 in FIG. Note that the polarizing plate 113 and the polarizing plate 149 may be upside down. Further, the surface of the protective film 146 may be subjected to antiglare treatment or antireflection treatment.

  FIG. 60A to FIG. 60C, FIG. 61A to FIG. 61B, and FIG. 62A to FIG. 62B show examples in which four polarizers are stacked.

  FIG. 60A illustrates an example in which the polarizing film 149 including the polarizing film 147 and the polarizing film 148 in FIG. 2C and the polarizing film 145 including the polarizing film 143 and the polarizing film 144 in FIG. is there. Note that the polarizing plate 149 and the polarizing plate 145 may be upside down. Further, an antiglare treatment or an antireflection treatment may be performed on the surface of the protective film 142.

  60B shows a polarizing plate 113 including the polarizing film 133 and the polarizing film 137 in FIG. 2A, and a polarizing plate 145 including the polarizing film 143 and the polarizing film 144 in FIG. This is an example of stacking layers. Note that the order of the upper and lower sides of the polarizing plate 113, the polarizing plate 114, and the polarizing plate 145 is not necessarily the same. Further, the surface of the protective film 146 may be subjected to antiglare treatment or antireflection treatment.

  60C shows a polarizing plate 113 including the polarizing film 133 and the polarizing film 137 in FIG. 2A, and a polarizing plate 149 including the polarizing film 147 and the polarizing film 148 in FIG. This is an example of stacking layers. Note that the order of the upper and lower sides of the polarizing plate 113, the polarizing plate 114, and the polarizing plate 149 is not necessarily the same. Further, the surface of the protective film 146 may be subjected to antiglare treatment or antireflection treatment.

  FIG. 61A includes a polarizing plate 113 including the polarizing film 133 in FIG. 2A and a polarizing film 143, a polarizing film 144, and a polarizing film 158 in which the polarizing film in FIG. This is an example in which a polarizing plate 159 is laminated. Note that the polarizing plate 113 and the polarizing plate 159 may be upside down. Further, an antiglare treatment or an antireflection treatment may be performed on the surface of the protective film 142.

  FIG. 61B includes a polarizing plate 113 including the polarizing film 133 in FIG. 2A and a polarizing film 147, a polarizing film 148, and a polarizing film 168 in which the polarizing film in FIG. This is an example in which a polarizing plate 169 is stacked. Note that the polarizing plate 113 and the polarizing plate 169 may be upside down. Further, the surface of the protective film 146 may be subjected to antiglare treatment or antireflection treatment.

  62A shows a polarizing plate 145 including the polarizing film 143 and the polarizing film 144 in FIG. 2B, and a polarizing plate 217 having the polarizing film 215 and the polarizing film 216 having the same structure as FIG. It is the example which laminated | stacked. Further, an antiglare treatment or an antireflection treatment may be performed on the surface of the protective film 142.

  62B shows a polarizing plate 149 including the polarizing film 147 and the polarizing film 148 in FIG. 2C, and a polarizing plate 227 including the polarizing film 225 and the polarizing film 226 having the same structure as FIG. It is the example which laminated | stacked. Further, an antiglare treatment or an antireflection treatment may be performed on the surface of the protective film 142.

  59 to 62, a retardation plate is provided between the substrate 111 and the polarizer if necessary.

  In FIGS. 63A to 63B and 64, a layer 176 having a display element is sandwiched between the substrate 111 and the substrate 112, and polarizers stacked above and below the layer 176 having a display element are stacked. An example with a different configuration will be shown. Although the retardation plate is not shown for simplification of the drawing, a retardation plate may be provided between the substrate and the polarizer if necessary.

  Further, in FIGS. 63A to 63B and 64, the number of polarizers provided on the substrate 111 and the substrate 112 is two, but may be three or more. In the case of three or more, the configuration shown in FIGS. 59 to 62 may be used.

  63A, the polarizing plate 113 including the polarizing film 133 and the polarizing plate 114 including the polarizing film 137 in FIG. 2A are stacked on the substrate 111 side. A polarizing plate 145 including the polarizing film 143 and the polarizing film 144 in FIG. 2B is provided on the substrate 112 side. Note that in the case where the display device has an upper and lower order, the polarizing plate 113 and the polarizing plate 114 and the polarizing plate 145 may be provided upside down. Further, antiglare treatment or antireflection treatment may be performed on the surfaces of the protective films 136 and 142.

  63B, the polarizing plate 113 including the polarizing film 133 and the polarizing plate 114 including the polarizing film 137 in FIG. 2A are stacked on the substrate 111 side. A polarizing plate 149 including the polarizing film 147 and the polarizing film 148 in FIG. 2C is provided on the substrate 112 side. Note that in the case where the display device has an upper and lower order, the polarizing plate 113 and the polarizing plate 114 and the polarizing plate 149 may be provided upside down. Further, antiglare treatment or antireflection treatment may be performed on the surfaces of the protective films 136 and 146.

  64, the polarizing plate 149 including the polarizing film 147 and the polarizing film 148 in FIG. 2C is provided on the substrate 111 side. A polarizing plate 145 including a polarizing film 143 and a polarizing film 144 is provided on the substrate 112 side. Note that in the case where the display device has a top-bottom order, the polarizing plate 149 and the polarizing plate 145 may be provided upside down. Further, antiglare treatment or antireflection treatment may be performed on the surfaces of the protective films 146 and 142.

  Needless to say, this embodiment can be applied to Embodiment 1, and this embodiment can be applied to other embodiments and examples in this specification.

[Embodiment 3]

  In this embodiment, the concept of the display device of the present invention will be described with reference to FIGS.

  3A is a cross-sectional view of a display device provided with a polarizer stacked with a retardation plate, and FIG. 3B is a perspective view of the display device.

  As shown in FIG. 3A, the display element 200 is sandwiched between a first substrate 201 and a second substrate 202 which are arranged to face each other.

  A light-transmitting substrate can be used as the first substrate 201 and the second substrate 202. For such a light-transmitting substrate, a material similar to that of the substrate 101 described in Embodiment 1 may be used.

  On the outside of the first substrate 201, that is, the side of the first substrate 201 that does not contact the display element 200, a retardation plate 211, a polarizer 203 that is a stacked polarizer, and a polarizer 204 are provided. The light is linearly polarized by a polarizer and circularly polarized by a retardation plate (also referred to as a retardation film or a wavelength plate). That is, the stacked polarizers can be described as stacked linear polarizers. The laminated polarizer refers to a state in which two or more polarizers are laminated. Embodiment 2 can be used for the structure of the stacked layers of the polarizers.

  3A to 3B illustrate an example in which two layers of polarizers are stacked, three or more layers may be stacked.

  The extinction coefficients of the first polarizer 203 and the second polarizer 204 are different. Or the wavelength distribution of the extinction coefficient of the 1st polarizer 203 and the 2nd polarizer 204 may differ.

  On the outside of the first substrate 201, a retardation plate 211, a first polarizer 203, and a second polarizer 204 are provided in this order. In the present embodiment, a quarter wavelength plate may be used as the phase difference plate 211.

  In this specification, the retardation plate and the stacked polarizers are combined and also referred to as a circularly polarizing plate having a stacked polarizer (linear polarizer).

  The absorption axis 221 of the first polarizer 203 and the absorption axis 222 of the second polarizer 204 are arranged in parallel. That is, the first polarizer 203 and the second polarizer 204, that is, the stacked polarizers are arranged so as to be parallel Nicols.

  Further, the slow axis 223 of the phase difference plate 211 is disposed so as to be shifted by 45 ° from the absorption axis 221 of the first polarizer 203 and the absorption axis 222 of the second polarizer 204.

  FIG. 4 shows a deviation angle between the absorption axis 221 and the slow axis 223. The slow axis 223 forms 135 °, the absorption axis 221 forms 90 °, and these are shifted by 45 °.

  Further, due to the characteristics of the phase difference plate, there is a fast axis in a direction orthogonal to the slow axis. Therefore, the arrangement with the polarizing plate can be determined using not only the slow axis but also the fast axis. In this embodiment, since the absorption axis and the slow axis are arranged so as to be shifted by 45 °, in other words, the absorption axis and the fast axis are arranged so as to be shifted by 135 °.

  In this specification, when the shift between the absorption axis and the slow axis is described, the above angle is assumed. However, as long as the same effect can be exhibited, the shift may be slightly deviated from the angle.

  Examples of the retardation plate 211 include a film in which liquid crystals are hybrid-aligned, a film in which liquid crystals are twisted and aligned, a uniaxial retardation film, or a biaxial retardation film. With such a retardation plate, the viewing angle of the display device can be increased.

  The uniaxial retardation film is formed by stretching a resin in one direction. The biaxial retardation film is formed by uniaxially stretching a resin in the transverse direction and then uniaxially stretching the resin in the longitudinal direction. The resin used here includes cycloolefin polymer (COP), polycarbonate (PC), polymethyl methacrylate (PMMA), polystyrene (PS), polyethersulfone (PES), polycarbonate (PC), polyphenylene sulfide (PPS), Examples include 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-aligning a discotic liquid crystal or a nematic liquid crystal with a triacetyl cellulose (TAC) film as a support. The retardation film can be attached to the substrate in a state of being attached to the polarizing plate.

  By laminating so that the transmission axes of the laminated polarizing plates are parallel Nicols, it is possible to reduce reflected light from external light as compared with a single polarizing plate. Therefore, the black display can be darkened, that is, the black luminance can be increased, and the contrast ratio of the display device can be increased.

  Further, in the present embodiment, since a quarter wavelength plate is used as the retardation plate, reflection of reflected light can be suppressed.

  Note that this embodiment can be implemented freely combining with any of the other embodiments and examples in this specification, if necessary.

[Embodiment 4]
In this embodiment mode, the concept of the display device of the present invention will be described.

  5A is a cross-sectional view of a display device provided with a polarizer having a stacked structure, and FIG. 5B is a perspective view of the display 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. 5A, a layer 300 having a liquid crystal element is sandwiched between a first substrate 301 and a second substrate 302 which are arranged to face each other. The substrates 301 and 302 are light-transmitting insulating substrates (hereinafter also referred to as light-transmitting substrates). 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 plastics typified by polyethylene-terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), polycarbonate (PC), or flexible synthetic resin such as acrylic is applied. can do.

  Stacked polarizers are provided on the outer sides of the substrates 301 and 302, that is, on the side not in contact with the layer 300 having a liquid crystal element. Note that in this embodiment, as the stacked polarizers, a structure in which a polarizing plate having one polarizing film illustrated in FIG. 2A is stacked is used. Of course, it goes without saying that the configuration shown in FIG. 2B or 2C may be used.

  A first polarizing plate 303 and a second polarizing plate 304 are provided on the first substrate 301 side, and a third polarizing plate 305 and a fourth polarizing plate 306 are provided on the second substrate 302 side. It has been.

  These polarizing plates 303 to 306 can be formed of a known material. For example, an adhesive surface, a TAC (triacetyl cellulose), a mixed layer of PVA (polyvinyl alcohol) and a dichroic dye, and a TAC are sequentially stacked from the substrate side. Can be used. Dichroic pigments include iodine and dichroic organic dyes. Moreover, a polarizing plate may be called a polarizing film from the shape.

  The extinction coefficients of the first polarizing plate 303 and the second polarizing plate 304 are different, and the extinction coefficients of the third polarizing plate 305 and the fourth polarizing plate 306 are different. Alternatively, the wavelength distributions of the extinction coefficients of the first polarizing plate 303 and the second polarizing plate 304 may be different, and the wavelength distributions of the extinction coefficients of the third polarizing plate 305 and the fourth polarizing plate 306 are different. It may be allowed.

  5A to 5B show an example in which two polarizing plates are laminated on one substrate, three or more may be laminated.

  As shown in FIG. 5B, the absorption axis 321 of the first polarizing plate 303 and the absorption axis 322 of the second polarizing plate 304 are stacked in parallel. This parallel state is called parallel Nicol. Similarly, the absorption axis 323 of the third polarizing plate 305 and the absorption axis 324 of the fourth polarizing plate 306 are stacked so as to be parallel, that is, parallel Nicol. Such laminated polarizing plates are arranged so that the absorption axes are orthogonal to each other. This orthogonal state is called crossed Nicol.

  Note that, due to the characteristics of the polarizing plate, there is a transmission axis in a direction orthogonal to the absorption axis. Therefore, even when the transmission axes are parallel to each other, it can be called parallel Nicol. Moreover, when the transmission axes are orthogonal to each other, it can be called crossed Nicols.

  Thus, by laminating | stacking so that the absorption axis of polarizing plates may become parallel Nicol, the light leakage of an absorption axis direction can be reduced. And by arrange | positioning laminated | stacked polarizing plates so that it may become crossed Nicols, light leakage can be reduced compared with the case where it arrange | positions at the crossed Nicols of polarizing plate single layers. For this reason, the contrast ratio of the display device can be increased.

  Note that this embodiment can be implemented freely combining with any of the other embodiments and examples in this specification, if necessary.

[Embodiment 5]
In this embodiment, a specific structure of the liquid crystal display device described in Embodiment 4 is described.

  FIG. 6 shows a cross-sectional view of a liquid crystal display device provided with a polarizing plate having a laminated structure.

  The liquid crystal display device illustrated in FIG. 6 includes a pixel portion 405 and a driver circuit portion 408. In the pixel portion 405 and the driver circuit portion 408, a base film 502 is provided over the substrate 501. For the substrate 501, an insulating substrate similar to that in Embodiments 1 to 4 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.

  The pixel portion 405 is provided with a transistor serving as a switching element with a base film 502 interposed therebetween. In this embodiment mode, a thin film transistor (TFT) is used as a transistor, which is called a switching TFT 503.

  A TFT can be manufactured by many 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 TFT having such a low concentration impurity region is referred to as an LDD (Light Doped Drain) structure. The low concentration impurity region can be formed so as to overlap with the gate electrode, and such a TFT is referred to as a GOLD (Gate Overlapped LDD) structure.

  Note that the TFT may be a top-gate TFT or a bottom-gate TFT, and may be manufactured as necessary.

  FIG. 6 shows a switching TFT 503 having a GOLD structure. The polarity of the switching TFT 503 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. Thereafter, a protective film that covers the gate electrode and the like is formed. A dangling bond of the crystalline semiconductor film can be terminated by the hydrogen element mixed in the protective film.

  In order to further improve the flatness, an interlayer insulating film 505 may be formed. For the interlayer insulating film 505, an organic material, an inorganic material, or a stacked structure thereof can be used. Then, an opening is formed in the interlayer insulating film 505, the protective film, and the gate insulating film, and a wiring connected to the impurity region is formed. In this way, the switching TFT 503 can be formed. Note that the present invention is not limited to the configuration of the switching TFT 503.

  Then, a pixel electrode 506 connected to the wiring is formed.

  In addition, the capacitor 504 can be formed at the same time as the switching TFT 503. In this embodiment, the capacitor 504 is formed using a stack of a conductive film, a protective film and interlayer insulating film 505, and a pixel electrode 506 which are formed at the same time as the gate electrode.

  In addition, by using a crystalline semiconductor film, the pixel portion 405 and the driver circuit portion 408 can be formed over the same substrate. In that case, the transistor in the pixel portion and the transistor in the driver circuit portion 408 are formed at the same time. A transistor used for the driver circuit portion 408 is referred to as a CMOS circuit 554 because it constitutes a CMOS circuit. The TFT constituting the CMOS circuit 554 can have the same structure as the switching TFT 503. Further, instead of the GOLD structure, an LDD structure can be used, and it is not always necessary to have the same configuration.

  An alignment film 508 is formed so as to cover the pixel electrode 506. The alignment film 508 is rubbed. This rubbing process may not be performed in the liquid crystal mode, for example, the VA mode.

  Next, a counter substrate 520 is prepared. A color filter 522 and a black matrix (BM) 524 can be provided inside the counter substrate 520, that is, on the side in contact with the liquid crystal. These can be manufactured by a known method. However, if formed by a droplet discharge method (typically, an inkjet method) in which a predetermined material is dropped, waste of the material can be eliminated. A color filter or the like is provided in a region where the switching TFT 503 is not disposed. That is, the color filter is provided so as to face the light transmission region, that is, the opening region. 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 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 524 is also provided to reduce reflection of external light due to the wiring of the switching TFT 503 and the CMOS circuit 554. Therefore, it is provided so as to overlap with the switching TFT 503 and the CMOS circuit 554. Note that the black matrix 524 may be formed so as to overlap with the capacitor 504. This is because reflection by the metal film included in the capacitor 504 can be prevented.

  Then, a counter electrode 523 and an alignment film 526 are provided. The alignment film 526 is rubbed. This rubbing process may not be performed in the liquid crystal mode, for example, the VA mode.

Note that a wiring, a gate electrode, a pixel electrode 506, and a counter electrode 523 included in the TFT are made of indium tin oxide ((Indium Tin Oxide (ITO)), indium zinc oxide (Indium Zinc) in which indium oxide is mixed with zinc oxide (ZnO). Oxide (IZO)), a conductive material in which silicon oxide (SiO 2 ) is mixed with indium oxide, organic indium, organic tin, 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 other metals or The alloy or the metal nitride can be selected.

  Such a counter substrate 520 is attached to the substrate 501 using a sealing material 528. The sealing material 528 can be drawn on the substrate 501 or the counter substrate 520 by using a dispenser or the like. In addition, a spacer 525 is provided in part of the pixel portion 405 and the driver circuit portion 408 in order to maintain a distance between the substrate 501 and the counter substrate 520. The spacer 525 has a columnar shape or a spherical shape.

  A liquid crystal 511 is injected between the substrate 501 and the counter substrate 520 bonded in this manner. When injecting liquid crystal, it is preferable to perform in a vacuum. The liquid crystal 511 can be formed by a method other than an injection method. For example, the liquid crystal 511 may be dropped and then the counter substrate 520 may be attached. Such a dropping method is preferably applied when handling a large substrate to which the injection method is difficult to apply.

  The liquid crystal 511 includes liquid crystal molecules, and the tilt of the liquid crystal molecules is controlled by the pixel electrode 506 and the counter electrode 523. Specifically, it is controlled by a voltage applied to the pixel electrode 506 and the counter electrode 523. Such control uses a control circuit provided in the drive circuit unit 408. Note that the control circuit is not necessarily formed over the substrate 501, and a circuit connected through the connection terminal 510 may be used. At this time, an anisotropic conductive film having conductive fine particles can be used to connect to the connection terminal 510. Further, the counter electrode 523 is electrically connected to a part of the connection terminal 510, so that the potential of the counter electrode 523 can be a common potential. For example, conduction can be achieved using the bump 537.

  Next, the configuration of the backlight unit 552 will be described. The backlight unit 552 includes a cold cathode tube, a hot cathode tube, a diode, an inorganic EL, and an organic EL as a light source 531 that emits light, a lamp reflector 532 for efficiently guiding the light to the light guide plate 535, A light guide plate 535 for guiding light to the entire surface, a diffusion plate 536 for reducing unevenness in brightness, and a reflection plate 534 for reusing light leaked under the light guide plate 535 are provided.

  A control circuit for adjusting the luminance of the light source 531 is connected to the backlight unit 552. The luminance of the light source 531 can be controlled by supplying a signal from the control circuit.

  In this embodiment, a structure in which a polarizing plate illustrated in FIG. 2A is stacked as a polarizer is used. Of course, stacked polarizers shown in FIGS. 2B and 2C may be used. As illustrated in FIG. 6, a stacked polarizing plate 516 is provided between the substrate 501 and the backlight unit 552, and a stacked polarizing plate 521 is also provided on the counter substrate 520.

  That is, the substrate 501 is provided with a polarizing plate 543 and a polarizing plate 544 stacked in this order from the substrate side. At this time, the laminated polarizing plates 543 and 544 are bonded so as to be in a parallel Nicol state.

  In addition, the counter substrate 520 is provided by stacking a polarizing plate 541 and a polarizing plate 542 as the stacked polarizing plates 521 in order from the substrate side. At this time, the laminated polarizing plates 541 and 542 are bonded so as to be in a parallel Nicol state.

  Further, the stacked polarizing plates 516 and 521 are arranged so as to be in a crossed Nicols state.

  Further, the extinction coefficients of the polarizing plate 541 and the polarizing plate 542 are different, and the extinction coefficients of the polarizing plate 543 and the polarizing plate 544 are different. Alternatively, the wavelength distributions of the extinction coefficients of the polarizing plates 541 and 542 may be different, or the wavelength distributions of the extinction coefficients of the polarizing plates 543 and 544 may be different.

  6 shows an example in which two polarizing plates are stacked on one substrate, three or more may be stacked.

  The contrast ratio can be increased by providing a laminated polarizing plate for such a liquid crystal display device. By using a polarizing plate with a different extinction coefficient or using a polarizing plate with a different wavelength distribution of the extinction coefficient, light in a wider wavelength range can be absorbed, and the contrast ratio is further increased. It is preferable at the point which can do.

  Note that this embodiment can be implemented freely combining with any of the other embodiments and examples in this specification, if necessary.

[Embodiment 6]
In this embodiment mode, a liquid crystal display device using a TFT having an amorphous semiconductor film, which is different from that in Embodiment Mode 5, is described.

  In addition, the same thing as Embodiment 5 is shown with the same code | symbol, and Embodiment 5 uses the thing which is not described in particular.

  FIG. 7 illustrates a structure of a transistor (hereinafter referred to as amorphous TFT) liquid crystal display device using an amorphous semiconductor film as a switching element. The pixel portion 405 is provided with a switching TFT 533 made of an amorphous TFT. The amorphous TFT can be formed by a known method. For example, in the case of the channel etch type, a gate electrode is formed on the base film 502, and the gate electrode is covered to cover the gate insulating film, the n-type semiconductor film, and the non-crystalline TFT. A crystalline semiconductor film, a source electrode, and a drain electrode are formed. An opening is formed in the n-type semiconductor film using the source electrode and the drain electrode. At this time, part of the amorphous semiconductor film is also removed, so that it is called a channel etch type. Thereafter, a protective film 507 is formed, and an amorphous TFT can be formed. An amorphous TFT also has a channel protection type, and a protective film is provided so that an amorphous semiconductor film is not removed when an opening is formed in an n-type semiconductor film using a source electrode and a drain electrode. Other configurations can be the same as those of the channel etch type.

  Then, an alignment film 508 is formed as in FIG. 6, and a rubbing process is performed. This rubbing process may not be performed in the liquid crystal mode, for example, the VA mode.

  Further, a counter substrate 520 is prepared similarly to FIG. A liquid crystal display device can be formed by sealing liquid crystal 511 between them.

  Similarly to FIG. 6, in this embodiment, a structure in which the polarizing plate illustrated in FIG. 2A is stacked is used as a polarizer. Of course, stacked polarizers shown in FIGS. 2B and 2C may be used. As illustrated in FIG. 6, a stacked polarizing plate 516 is provided between the substrate 501 and the backlight unit 552, and a stacked polarizing plate 521 is also provided on the counter substrate 520.

  That is, the substrate 501 is provided with a polarizing plate 543 and a polarizing plate 544 stacked in this order from the substrate side. At this time, the laminated polarizing plates 543 and 544 are bonded so as to be in a parallel Nicol state.

  In addition, the counter substrate 520 is provided by stacking a polarizing plate 541 and a polarizing plate 542 as the stacked polarizing plates 521 in order from the substrate side. At this time, the laminated polarizing plates 541 and 542 are bonded so as to be in a parallel Nicol state.

  Further, the stacked polarizing plates 516 and 521 are arranged so as to be in a crossed Nicols state.

  Further, the extinction coefficients of the polarizing plate 541 and the polarizing plate 542 are different, and the extinction coefficients of the polarizing plate 543 and the polarizing plate 544 are different. Alternatively, the wavelength distributions of the extinction coefficients of the polarizing plates 541 and 542 may be different, or the wavelength distributions of the extinction coefficients of the polarizing plates 543 and 544 may be different.

  FIG. 7 shows an example in which two polarizing plates are stacked on one substrate, but three or more polarizing plates may be stacked.

  In this manner, when an amorphous TFT is used as the switching TFT 533 to form a liquid crystal display device, an IC 421 formed from a silicon wafer can be mounted as a driver on the driver circuit portion 408 in consideration of operation performance. it can. For example, a signal for controlling the switching TFT 533 can be supplied by connecting a wiring included in the IC 421 and a wiring connected to the switching TFT 533 using an anisotropic conductor including the conductive fine particles 422. . Note that the mounting method of the IC 421 is not limited to this, and can be mounted by a wire bonding method.

  Furthermore, it can be connected to the control circuit via the connection terminal 510. At this time, an anisotropic conductive film having conductive fine particles 422 can be used to connect to the connection terminal 510.

  The other configuration is the same as that in FIG.

The contrast ratio can be increased by providing a laminated polarizing plate for such a liquid crystal display device. Further, in the present invention, the plurality of polarizing plates can be a polarizing plate having a laminated structure, by using a polarizing plate having a different extinction coefficient, or by using a polarizing plate having a different wavelength distribution of the extinction coefficient, This is preferable in that light in a wider wavelength range can be absorbed and the contrast ratio can be further increased.

  Note that this embodiment can be implemented freely combining with any of the other embodiments and examples in this specification, if necessary.

[Embodiment 7]
In this embodiment mode, the concept of the display device of the present invention will be described.

  8A is a cross-sectional view of a display device provided with a polarizer having a stacked structure, and FIG. 8B is a perspective view of the display 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. 8A, a layer 160 having a liquid crystal element is sandwiched between a first substrate 161 and a second substrate 162 which are arranged to face each other. A light-transmitting substrate is used as the substrates 161 and 162, and a glass substrate such as barium borosilicate glass or alumino borosilicate glass, a quartz substrate, or the like can be used as such a light-transmitting substrate. For the light-transmitting substrate, polyethylene-terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), plastic (typified by polycarbonate (PC)), and flexible synthetic materials such as acrylic. A substrate made of a resin can be applied.

  A stacked polarizer is provided on the outside of each of the substrates 161 and 162, that is, on the side not in contact with the layer 160 having a liquid crystal element. Note that in this embodiment, as the stacked polarizers, a structure in which a polarizing plate having one polarizing film illustrated in FIG. 2A is stacked is used. Of course, it goes without saying that the configuration shown in FIG. 2B or 2C may be used.

  A retardation plate (also referred to as a retardation film or a wavelength plate) and a laminated polarizing plate are sequentially provided on the outer sides of the substrates 161 and 162, that is, on the side not in contact with the layer 160 having a liquid crystal element. A first retardation plate 171, a first polarizing plate 163, and a second polarizing plate 164 are provided in this order on the first substrate 161 side. A second retardation plate 172, a third polarizing plate 165, and a fourth polarizing plate 166 are sequentially provided on the second substrate 162 side. The phase difference plate is used for the purpose of widening the viewing angle or the antireflection effect. When the phase difference plate is used for antireflection, quarter wave plates are used as the phase difference plates 171 and 172.

  These polarizing plates 163 to 166 can be formed of a known material. For example, an adhesive surface, a TAC (triacetyl cellulose), a mixed layer of PVA (polyvinyl alcohol) and a dichroic dye, and a TAC are sequentially laminated from the substrate side. Can be used. Dichroic pigments include iodine and dichroic organic dyes. Moreover, a polarizing plate may be called a polarizing film from the shape.

  The extinction coefficients of the first polarizing plate 163 and the second polarizing plate 164 are different, and the extinction coefficients of the third polarizing plate 165 and the fourth polarizing plate 166 are different. Alternatively, the wavelength distribution of the extinction coefficient between the first polarizing plate 163 and the second polarizing plate 164 may be different, and the wavelength distribution of the extinction coefficient between the third polarizing plate 165 and the fourth polarizing plate 166 is different. It may be.

  8A to 8B show an example in which two polarizing plates are laminated on one substrate, three or more may be laminated.

  Examples of the retardation film include a film in which liquid crystals are hybrid-aligned, a film in which liquid crystals are twisted and aligned, a uniaxial retardation film, or a biaxial retardation film. Such a retardation film can achieve a wide viewing angle of the display device.

  The uniaxial retardation film is formed by stretching a resin in one direction. The biaxial retardation film is formed by uniaxially stretching a resin in the transverse direction and then uniaxially stretching the resin in the longitudinal direction. The resin used here includes cycloolefin polymer (COP), polycarbonate (PC), polymethyl methacrylate (PMMA), polystyrene (PS), polyethersulfone (PES), polycarbonate (PC), polyphenylene sulfide (PPS), Examples thereof include 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-aligning a discotic liquid crystal or a nematic liquid crystal with a triacetyl cellulose (TAC) film as a support. The retardation film can be attached to the translucent substrate in a state of being attached to the polarizing plate.

  Next, in the perspective view shown in FIG. 8B, the absorption axis 181 of the first polarizing plate 163 and the absorption axis 182 of the second polarizing plate 164 are stacked so as to be parallel. This parallel state is called parallel Nicol. Similarly, the absorption axis 183 of the third polarizing plate 165 and the absorption axis 184 of the fourth polarizing plate 166 are stacked so as to be parallel, that is, parallel Nicol.

  The polarizing plates laminated in this way are arranged so as to be parallel Nicols.

  The laminated polarizing plates, that is, the opposing polarizing plates are arranged so that the absorption axes are orthogonal to each other. This orthogonal state is called crossed Nicol.

  Note that, due to the characteristics of the polarizing plate, there is a transmission axis in a direction orthogonal to the absorption axis. Therefore, even when the transmission axes are parallel to each other, it can be called parallel Nicol. Moreover, when the transmission axes are orthogonal to each other, it can be called crossed Nicols.

  By laminating so that the absorption axes of the laminated polarizing plates are parallel Nicols, light leakage in the absorption axis direction can be reduced. And by arrange | positioning the polarizing plates which oppose so that it may become cross Nicol, light leakage can be reduced compared with cross Nicol of polarizing plate single layers. For this reason, the contrast ratio of the display device can be increased.

  Furthermore, since the present invention includes a retardation plate, a display device having an antireflection effect or a display device having a wide viewing angle can be provided.

  Note that this embodiment can be implemented freely combining with any of the other embodiments and examples in this specification, if necessary.

[Embodiment 8]
In this embodiment, a specific structure of the liquid crystal display device described in Embodiment 7 is described.

  Note that in the liquid crystal display device illustrated in FIG. 9, the same components as those in FIG. 6 are denoted by the same reference numerals, and the description of FIG.

  FIG. 9 is a cross-sectional view of a liquid crystal display device provided with stacked polarizing plates.

  The liquid crystal display device includes a pixel portion 405 and a driver circuit portion 408. In the pixel portion 405 and the driver circuit portion 408, a base film 502 is provided over the substrate 501. For the substrate 501, an insulating substrate similar to that in Embodiment 7 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.

  The pixel portion 405 is provided with a transistor serving as a switching element with a base film 502 interposed therebetween. In this embodiment mode, a thin film transistor ((Thin Film Transistor (TFT))) is used as a transistor, which is referred to as a switching TFT 503. The TFT can be manufactured by a number of methods, for example, a crystalline semiconductor as an active layer A gate electrode is provided over the crystalline semiconductor film through a gate insulating film, and an impurity element can be added to the active layer using the gate electrode. It is not necessary to form a mask for adding the impurity element by adding the impurity element used.The gate electrode can have a single layer structure or a stacked structure.The impurity region can be controlled by controlling its concentration. A high-concentration impurity region and a low-concentration impurity region can be used, and thus a TF having a low-concentration impurity region T is referred to as an LDD (Light Doped Drain) structure, and the low concentration impurity region can be formed so as to overlap with the gate electrode, and such a TFT is referred to as a GOLD (Gate Overlapped LDD) structure.

  Note that the TFT may be a top-gate TFT or a bottom-gate TFT, and may be manufactured as necessary.

  FIG. 9 shows a switching TFT 503 having a GOLD structure. The polarity of the switching TFT 503 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. Thereafter, a protective film that covers the gate electrode and the like is formed. A dangling bond of the crystalline semiconductor film can be terminated by the hydrogen element mixed in the protective film.

  In order to further improve the flatness, an interlayer insulating film 505 may be formed. For the interlayer insulating film 505, an organic material, an inorganic material, or a stacked structure thereof can be used. Then, an opening is formed in the interlayer insulating film 505, the protective film, and the gate insulating film, and a wiring connected to the impurity region is formed. In this way, the switching TFT 503 can be formed. Note that the present invention is not limited to the configuration of the switching TFT 503.

Then, a pixel electrode 506 connected to the wiring is formed.

  In addition, the capacitor 504 can be formed at the same time as the switching TFT 503. In this embodiment, the capacitor 504 is formed using a stack of a conductive film, a protective film and interlayer insulating film 505, and a pixel electrode 506 which are formed at the same time as the gate electrode.

  In addition, by using a crystalline semiconductor film, the pixel portion 405 and the driver circuit portion 408 can be formed over the same substrate. In that case, the transistor in the pixel portion 405 and the transistor in the driver circuit portion 408 are formed at the same time. A transistor used for the driver circuit portion 408 is referred to as a CMOS circuit 554 because it constitutes a CMOS circuit. The TFT constituting the CMOS circuit 554 can have the same structure as the switching TFT 503. Further, instead of the GOLD structure, an LDD structure can be used, and it is not always necessary to have the same configuration.

  An alignment film 508 is formed so as to cover the pixel electrode 506. The alignment film 508 is rubbed. This rubbing process may not be performed in the liquid crystal mode, for example, the VA mode.

  Next, a counter substrate 520 is prepared. A color filter 522 and a black matrix (BM) 524 can be provided inside the counter substrate 520, that is, on the side in contact with the liquid crystal. These can be manufactured by a known method. However, if formed by a droplet discharge method (typically, an inkjet method) in which a predetermined material is dropped, waste of the material can be eliminated. A color filter or the like is provided in a region where the switching TFT 503 is not disposed. That is, the color filter is provided so as to face the light transmission region, that is, the opening region. 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 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 524 is also provided to reduce reflection of external light due to the wiring of the switching TFT 503 and the CMOS circuit 554. Therefore, it is provided so as to overlap with the switching TFT 503 and the CMOS circuit 554. Note that the black matrix 524 may be formed so as to overlap with the capacitor 504. This is because reflection by the metal film included in the capacitor 504 can be prevented.

  Then, a counter electrode 523 and an alignment film 526 are provided. The alignment film 526 is rubbed. This rubbing process may not be performed in the liquid crystal mode, for example, the VA mode.

Note that a wiring, a gate electrode, a pixel electrode 506, and a counter electrode 523 included in the TFT are indium tin oxide (ITO), indium oxide zinc oxide (indium zinc oxide (IZO)) mixed with indium oxide and zinc oxide (ZnO), Conductive material in which silicon oxide (SiO 2 ) is mixed with indium oxide, organic indium, organic tin, 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), etc. or their alloys, or their metals You can choose from nitrides.

  Such a counter substrate 520 is attached to the substrate 501 using a sealing material 528. The sealing material 528 can be drawn on the substrate 501 or the counter substrate 520 by using a dispenser or the like. In addition, a spacer 525 is provided in part of the pixel portion 405 and the driver circuit portion 408 in order to maintain a distance between the substrate 501 and the counter substrate 520. The spacer 525 has a columnar shape or a spherical shape.

  A liquid crystal 511 is injected between the substrate 501 and the counter substrate 520 bonded in this manner. When injecting liquid crystal, it is preferable to perform in a vacuum. The liquid crystal 511 can be formed by a method other than an injection method. For example, the liquid crystal 511 may be dropped and then the counter substrate 520 may be attached. Such a dropping method is preferably applied when handling a large substrate to which the injection method is difficult to apply.

  The liquid crystal 511 includes liquid crystal molecules, and the tilt of the liquid crystal molecules is controlled by the pixel electrode 506 and the counter electrode 523. Specifically, it is controlled by a voltage applied to the pixel electrode 506 and the counter electrode 523. Such control uses a control circuit provided in the drive circuit unit 408. Note that the control circuit is not necessarily formed over the substrate 501, and a circuit connected through the connection terminal 510 may be used. At this time, an anisotropic conductive film having conductive fine particles can be used to connect to the connection terminal 510. Further, the counter electrode 523 is electrically connected to a part of the connection terminal 510, so that the potential of the counter electrode 523 can be a common potential. For example, conduction can be achieved using the bump 537.

  Next, the configuration of the backlight unit 552 will be described. The backlight unit 552 includes a cold cathode tube, a hot cathode tube, a diode, an inorganic EL, and an organic EL as a light source 531 that emits light, a lamp reflector 532 for efficiently guiding the light to the light guide plate 535, A light guide plate 535 for guiding light to the entire surface, a diffusion plate 536 for reducing unevenness in brightness, and a reflection plate 534 for reusing light leaked under the light guide plate 535 are provided.

  A control circuit for adjusting the luminance of the light source 531 is connected to the backlight unit 552. The luminance of the light source 531 can be controlled by supplying a signal from the control circuit.

  In this embodiment, a structure in which a polarizing plate illustrated in FIG. 2A is stacked as a polarizer is used. Of course, stacked polarizers shown in FIGS. 2B and 2C may be used. As shown in FIG. 9, a retardation plate 547 and a laminated polarizing plate 516 are provided between the substrate 501 and the backlight unit 552, and a retardation plate 546 and a laminated polarizing plate 521 are also provided on the counter substrate 520. It has been. The laminated polarizing plate and the retardation film can be bonded to each of the substrates 501 and 520 in a state of being bonded together.

  That is, the substrate 501 is provided with a retardation plate 547 and a laminate of a polarizing plate 543 and a polarizing plate 544 as the stacked polarizing plates 516 in order from the substrate side. At this time, the laminated polarizing plates 543 and 544 are bonded so as to be in a parallel Nicol state.

  In addition, the counter substrate 520 is provided with a retardation plate 546 and a stack of a polarizing plate 541 and a polarizing plate 542 as the stacked polarizing plates 521 in order from the substrate side. At this time, the laminated polarizing plates 541 and 542 are bonded so as to be in a parallel Nicol state.

  Further, the stacked polarizing plates 516 and 521 are arranged so as to be in a crossed Nicols state.

  Further, the extinction coefficients of the polarizing plate 541 and the polarizing plate 542 are different, and the extinction coefficients of the polarizing plate 543 and the polarizing plate 544 are different. Alternatively, the wavelength distributions of the extinction coefficients of the polarizing plates 541 and 542 may be different, or the wavelength distributions of the extinction coefficients of the polarizing plates 543 and 544 may be different.

  FIG. 9 shows an example in which two polarizing plates are stacked on one substrate, but three or more polarizing plates may be stacked.

  By having the laminated polarizing plates, the contrast ratio can be increased. In addition, the retardation plate can provide a display device having an antireflection effect or a display device having a wide viewing angle.

  Note that this embodiment can be implemented freely combining with any of the other embodiments and examples in this specification, if necessary.

[Embodiment 9]
In this embodiment mode, a liquid crystal display device using a TFT having an amorphous semiconductor film, which is different from that in Embodiment Mode 8, is described.

  FIG. 10 illustrates a structure of a transistor (hereinafter referred to as amorphous TFT) liquid crystal display device using an amorphous semiconductor film as a switching element. The pixel portion 405 is provided with a switching TFT 533 made of an amorphous TFT. The amorphous TFT can be formed by a known method. For example, in the case of the channel etch type, a gate electrode is formed on the base film 502, and the gate electrode is covered to cover the gate insulating film, the n-type semiconductor film, and the non-crystalline TFT. A crystalline semiconductor film, a source electrode, and a drain electrode are formed. An opening is formed in the n-type semiconductor film using the source electrode and the drain electrode. At this time, part of the amorphous semiconductor film is also removed, so that it is called a channel etch type. Thereafter, a protective film 507 is formed, and an amorphous TFT can be formed. An amorphous TFT also has a channel protection type, and a protective film is provided so that an amorphous semiconductor film is not removed when an opening is formed in an n-type semiconductor film using a source electrode and a drain electrode. Other configurations can be the same as those of the channel etch type.

  Then, an alignment film 508 is formed as in FIG. 9, and a rubbing process is performed. This rubbing process may not be performed depending on the liquid crystal mode.

  In addition, a counter substrate 520 is prepared similarly to FIG. A liquid crystal display device can be formed by sealing liquid crystal 511 between them.

  In this embodiment, a structure in which a polarizing plate illustrated in FIG. 2A is stacked as a polarizer is used. Of course, stacked polarizers shown in FIGS. 2B and 2C may be used. As shown in FIG. 10, similarly to FIG. 9, a retardation plate 547 and a laminated polarizing plate 516 are provided between the substrate 501 and the backlight unit 552, and the retardation plate 546 and the laminated plate are also provided on the counter substrate 520. A polarizing plate 521 is provided. The laminated polarizing plate and the retardation film can be bonded to each of the substrates 501 and 520 in a state of being bonded together.

  That is, the substrate 501 is provided with a retardation plate (also referred to as a retardation film or a wavelength plate) 547 and a laminate of a polarizing plate 543 and a polarizing plate 544 as the stacked polarizing plates 516 in order from the substrate side. Yes. At this time, the laminated polarizing plates 543 and 544 are bonded so as to be in a parallel Nicol state.

  In addition, the counter substrate 520 is provided with a retardation plate 546 and a stack of a polarizing plate 541 and a polarizing plate 542 as the stacked polarizing plates 521 in order from the substrate side. At this time, the laminated polarizing plates 541 and 542 are bonded so as to be in a parallel Nicol state.

  Further, the stacked polarizing plates 516 and 521 are arranged so as to be in a crossed Nicols state.

  Further, the extinction coefficients of the polarizing plate 541 and the polarizing plate 542 are different, and the extinction coefficients of the polarizing plate 543 and the polarizing plate 544 are different. Alternatively, the wavelength distributions of the extinction coefficients of the polarizing plates 541 and 542 may be different, or the wavelength distributions of the extinction coefficients of the polarizing plates 543 and 544 may be different.

  FIG. 10 shows an example in which two polarizing plates are laminated on one substrate, but three or more polarizing plates may be laminated.

  By having the laminated polarizing plates, the contrast ratio can be increased. In addition, a display device with a wide viewing angle can be provided by the retardation plate.

  In this manner, when an amorphous TFT is used as the switching TFT 533 to form a liquid crystal display device, an IC 421 formed from a silicon wafer can be mounted as a driver on the driver circuit portion 408 in consideration of operation performance. it can. For example, a signal for controlling the switching TFT 533 can be supplied by connecting a wiring included in the IC 421 and a wiring connected to the switching TFT 533 using an anisotropic conductor including the conductive fine particles 422. . Note that the IC mounting method is not limited to this, and the IC can be mounted by a wire bonding method.

  Furthermore, it can be connected to the control circuit via the connection terminal 510. At this time, an anisotropic conductive film having conductive fine particles 422 can be used to connect to the connection terminal 510.

  Other configurations are the same as those in FIG.

  Note that this embodiment can be implemented freely combining with any of the other embodiments and examples in this specification, if necessary.

[Embodiment 10]
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.

  The backlight of this embodiment mode is used as the backlight unit 552 described in Embodiment Mode 5, Embodiment Mode 6, Embodiment Mode 8, and Embodiment Mode 9.

  As shown in FIG. 11, the backlight unit 552 can use a cold cathode fluorescent lamp 571 as a light source. In addition, a lamp reflector 532 can be provided in order to reflect light from the cold cathode fluorescent lamp 571 efficiently. The cold cathode tube 571 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. 12, the backlight unit 552 can use a diode (LED) 572 as a light source. For example, white diodes (W) 572 are arranged at predetermined intervals. In addition, a lamp reflector 532 can be provided in order to efficiently reflect light from the diode (W) 572.

  Further, as shown in FIG. 13A, the backlight unit 552 includes RGB diodes (LEDs) as light sources, that is, a diode (R) 573 that emits red, a diode (G) 574 that emits green, and a diode that emits blue. (B) 575 can be used. By using the diodes (LEDs) 573, 574, and 575 of each color RGB, color reproducibility can be improved as compared with only the diode (W) 572 that emits white. A lamp reflector 532 can be provided in order to efficiently reflect light from the diode (R) 573, the diode (G) 574, and the diode (B) 575.

  Further, as shown in FIG. 13B, when the diodes (LEDs) 573, 574, and 575 of the respective colors RGB are used as the light source, it is not necessary to have the same number and arrangement. For example, a plurality of colors with low emission intensity (for example, green) may be arranged.

  Further, a diode (W) 572 that emits white and diodes (LEDs) 573, 574, and 575 of each color RGB may be used in combination.

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

  A diode is suitable for a large display device because of its high luminance. Further, since the color purity of each of the RGB colors is good, the color reproducibility is superior to that of a cold cathode tube, and the arrangement area can be reduced. Therefore, when applied 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 FIGS. 11, 12, and 13A to 13B. For example, when a backlight having a diode is mounted on a large display device, the diode can be arranged on the back surface of the substrate. At this time, the diodes can maintain a predetermined interval, and the diodes of the respective colors can be arranged in order. The color reproducibility can be improved by the arrangement of the diodes.

  By providing a stacked polarizer for a display device using such a backlight, an image with a high contrast ratio can be provided. In particular, a backlight including a 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.

  Note that this embodiment can be implemented freely combining with any of the other embodiments and examples in this specification, if necessary.

[Embodiment 11]
In this embodiment mode, the concept of the reflective liquid crystal display device of the present invention will be described with reference to FIGS.

  14A is a cross-sectional view of a liquid crystal display device provided with stacked polarizers, and FIG. 14B is a perspective view of the display device.

  As shown in FIG. 14A, a layer 600 having a liquid crystal element is sandwiched between a first substrate 601 and a second substrate 602 which are arranged to face each other.

  A light-transmitting substrate can be used as the first substrate 601 and the second substrate 602. As such a light-transmitting substrate, a glass substrate such as barium borosilicate glass or alumino borosilicate glass, a quartz substrate, or the like can be used. For the light-transmitting substrate, polyethylene-terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), plastic (typified by polycarbonate (PC)), and flexible synthetic materials such as acrylic. A substrate made of a resin can be applied.

  On the outside of the substrate 601, that is, the side not in contact with the layer 600 having a liquid crystal element, a retardation plate (also referred to as a “retardation film” or a “wavelength plate”) and a stacked polarizer are sequentially provided. In this embodiment, as the stacked polarizer, a structure in which the polarizing plates illustrated in FIG. 2A are stacked is used. Of course, the structure shown in FIG. 2B or 2C may be used as necessary.

  A retardation film 621, a first polarizing plate 603, and a second polarizing plate 604 are provided in this order on the first substrate 601 side. The slow axis of the phase difference plate 621 is indicated by 653. External light passes through the second polarizing plate 604, the first polarizing plate 603, the retardation plate 621, and the substrate 601, and enters the layer 600 having a liquid crystal element. Display is performed by being reflected by the reflective material provided on the second substrate 602.

  The polarizing plates 603 and 604 are linear polarizing plates, respectively, and are the same as the polarizing plates 113 and 114 in FIG.

  Further, the extinction coefficients of the polarizing plates 603 and 604 are different. Alternatively, the wavelength distribution of the extinction coefficient of the polarizing plates 603 and 604 may be varied.

  14A to 14B illustrate an example in which two polarizing plates are stacked on one substrate, three or more may be stacked.

  Examples of the retardation film (also referred to as retardation film) 621 include a uniaxial retardation film (for example, a quarter wavelength plate).

  The uniaxial retardation film is formed by stretching a resin in one direction. The resin used here includes cycloolefin polymer (COP), polycarbonate (PC), polymethyl methacrylate (PMMA), polystyrene (PS), polyethersulfone (PES), polycarbonate (PC), polyphenylene sulfide (PPS), Examples thereof include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polypropylene (PP), polyphenylene oxide (PPO), polyarylate (PAR), polyimide (PI), polytetrafluoroethylene (PTFE) and the like.

  The retardation film can be attached to the substrate in a state of being attached to the polarizing plate.

  Next, in the perspective view shown in FIG. 14B, the absorption axis 651 of the first linearly polarizing plate 603 and the absorption axis 652 of the second linearly polarizing plate 604 are stacked so as to be parallel. . This parallel state is called parallel Nicol.

  The polarizing plates laminated in this way are arranged so as to be parallel Nicols.

  Note that, due to the characteristics of the polarizing plate, there is a transmission axis in a direction orthogonal to the absorption axis. Therefore, even when the transmission axes are parallel to each other, it can be called parallel Nicol.

  By stacking the polarizing plates so that the absorption axes of the stacked polarizing plates are parallel Nicols, the black display can be darkened, that is, the black luminance can be increased, and thus the contrast ratio of the display device can be increased. it can.

  Furthermore, since this invention has a phase difference plate, reflection of reflected light can be suppressed.

  Note that this embodiment can be implemented freely combining with any of the other embodiments and examples in this specification, if necessary.

[Embodiment 12]
In this embodiment, a specific structure of the reflective liquid crystal display device described in Embodiment 11 is described.

  FIG. 15 shows a cross-sectional view of a reflective liquid crystal display device provided with stacked polarizers.

  The reflective liquid crystal display device in this embodiment includes a pixel portion 405 and a driver circuit portion 408. In the pixel portion 405 and the driver circuit portion 408, a base film 702 is provided over the substrate 701. As the substrate 701, a substrate similar to that in Embodiment 11 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 portion 405, a transistor serving as a switching element is provided with a base film 702 interposed therebetween. In this embodiment mode, a thin film transistor (TFT) is used as the transistor, which is called a switching TFT 703.

  The TFT used for the switching TFT 703 and the driver circuit portion 408 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 region can be formed by adding an impurity element to a crystalline semiconductor film to be an active layer using a 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.

  Note that the TFT may be a top gate TFT or a bottom gate TFT, and may be formed as necessary.

  The impurity region can be a high concentration impurity region and a low concentration impurity region by controlling the concentration thereof. A TFT having such a low concentration impurity region is referred to as an LDD (Light Doped Drain) structure. The low-concentration impurity region can be formed so as to overlap with the gate electrode. Such a TFT is referred to as a GOLD (Gate Overlapped LDD) structure in this specification.

  FIG. 15 shows a switching TFT 703 having a GOLD structure. The polarity of the switching TFT 703 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.

  Thereafter, a protective film that covers the gate electrode and the like is formed. A dangling bond of the crystalline semiconductor film can be terminated by the hydrogen element mixed in the protective film.

  Further, an interlayer insulating film 705 may be formed in order to improve flatness. For the interlayer insulating film 705, an organic material, an inorganic material, or a stacked structure thereof can be used.

  Then, openings are formed in the interlayer insulating film 705, the protective film, and the gate insulating film, and wirings connected to the impurity regions are formed. In this way, the switching TFT 703 can be formed. Note that the present invention is not limited to the configuration of the switching TFT 703.

  Then, a pixel electrode 706 connected to the wiring is formed.

  In addition, the capacitor 704 can be formed at the same time as the switching TFT 703. In this embodiment, the capacitor 704 is formed using a stack of a conductive film, a protective film and interlayer insulating film 705, and a pixel electrode 706 that are formed at the same time as the gate electrode.

  In addition, by using a crystalline semiconductor film, the pixel portion and the driver circuit portion can be formed over the same substrate. In that case, the thin film transistor in the pixel portion and the thin film transistor in the driver circuit portion 408 are formed at the same time.

  A thin film transistor used for the driver circuit portion 408 is referred to as a CMOS circuit 754 because it forms a CMOS circuit. The TFT constituting the CMOS circuit 754 can have the same structure as the switching TFT 703. Further, instead of the GOLD structure, an LDD structure can be used, and it is not always necessary to have the same configuration.

  An alignment film 708 is formed so as to cover the pixel electrode 706. The alignment film 708 is rubbed. This rubbing process may not be performed in the liquid crystal mode, for example, the VA mode.

  Next, a counter substrate 720 is prepared. A color filter 722 and a black matrix (BM) 724 can be provided inside the counter substrate 720, that is, on the side in contact with the liquid crystal. The color filter 722 and the black matrix 724 can be manufactured by a publicly known method, but if formed by a droplet discharge method (typically, an inkjet method) in which a predetermined material is dropped, waste of the material can be eliminated. .

  The color filter 722 is provided in a region where the switching TFT 703 is not disposed. That is, the color filter 722 is provided so as to face the light transmission region, that is, the opening region. Note that the color filter 722 may be formed of a material exhibiting red (R), green (G), and blue (B) when the liquid crystal display device is used for full-color display. What is necessary is just to form from the material which exhibits a color.

  In addition, when the successive additive color mixing method (field sequential method) for displaying colors by time division is adopted, a color filter may not be provided.

  The black matrix 724 is also provided to reduce reflection of external light due to the wiring of the switching TFT 703 and the CMOS circuit 754. Therefore, it is provided so as to overlap with the switching TFT 703 and the CMOS circuit 754. Note that the black matrix 724 may be formed so as to overlap with the capacitor 704. This is because reflection by the metal film included in the capacitor 704 can be prevented.

  Then, a counter electrode 723 and an alignment film 726 are provided. The alignment film 726 is rubbed. This rubbing process may not be performed in the liquid crystal mode, for example, the VA mode.

  Note that the pixel electrode 706 is formed using a reflective conductive material. Such reflective conductive materials include tungsten (W), molybdenum (Mo), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), cobalt It can be selected from metals such as (Co), nickel (Ni), titanium (Ti), platinum (Pt), aluminum (Al), copper (Cu), silver (Ag), alloys thereof, or metal nitrides thereof. . By the pixel electrode 706 which is a reflective electrode, external light is reflected above the switching TFT 703 and the CMOS circuit 754 and toward the counter substrate 720.

  A wiring and a gate electrode included in the TFT may be formed using a material similar to that of the pixel electrode 706.

The counter electrode 723 is formed using a light-transmitting conductive material. As such a light-transmitting conductive material, indium tin oxide (Indium Tin Oxide (ITO)), a conductive material in which zinc oxide (ZnO) is mixed with indium oxide, and a conductive material in which indium oxide is mixed with silicon oxide (SiO 2 ). Materials, organic indium, organic tin, etc. can be selected.

  Such a counter substrate 720 is attached to the substrate 701 with the use of a sealing material 728. The sealant 728 can be formed over the substrate 701 or the counter substrate 720 using a dispenser or the like. In addition, a spacer 725 is provided in part of the pixel portion 405 and the driver circuit portion 408 in order to maintain a distance between the substrate 701 and the counter substrate 720. The spacer 725 has a columnar shape or a spherical shape.

  A liquid crystal 711 is injected between the substrate 701 and the counter substrate 720 bonded together in this manner. When injecting liquid crystal, it is preferable to perform in a vacuum. The liquid crystal 711 can be formed by a method other than an injection method. For example, the liquid crystal 711 may be dropped and then the counter substrate 720 may be attached. Such a dropping method is preferably applied when handling a large substrate to which the injection method is difficult to apply.

  The liquid crystal 711 includes liquid crystal molecules, and the tilt of the liquid crystal molecules is controlled by the pixel electrode 706 and the counter electrode 723. Specifically, it is controlled by a voltage applied to the pixel electrode 706 and the counter electrode 723. Such control uses a control circuit provided in the drive circuit unit 408. Note that the control circuit is not necessarily formed over the substrate 701, and a circuit connected through the connection terminal 710 may be used. At this time, an anisotropic conductive film having conductive fine particles can be used to connect to the connection terminal 710. Alternatively, the counter electrode 723 may be electrically connected to part of the connection terminal 710 so that the potential of the counter electrode 723 may be a common potential.

  In this embodiment, a structure in which a polarizing plate illustrated in FIG. 2A is stacked as a polarizer is used. Of course, stacked polarizers shown in FIGS. 2B and 2C may be used.

  The counter substrate 720 is provided with a retardation plate 741, a polarizing plate 742 that is a stacked polarizing plate, and a polarizing plate 743 in order from the substrate side. The laminated polarizing plate and the retardation plate 741 can be bonded to the counter substrate 720 in a state of being bonded to each other. At this time, the stacked polarizing plates 742 and 743 are bonded so as to be in a parallel Nicol state.

  Further, the extinction coefficients of the polarizing plates 742 and 743 are different. Alternatively, the wavelength distribution of the extinction coefficient of the polarizing plates 742 and 743 may be different.

  FIG. 15 shows an example in which two polarizing plates are stacked on one substrate, but three or more polarizing plates may be stacked.

  By having the laminated polarizing plates, the contrast ratio can be increased. In addition, the retardation film can provide a display device with higher black luminance.

  Note that this embodiment mode can be combined with Embodiment Mode 11 if necessary.

  Further, this embodiment can be implemented in combination with any of the other embodiments and examples in this specification as needed.

[Embodiment 13]
In this embodiment mode, a liquid crystal display device using a TFT having an amorphous semiconductor film, which is different from that in Embodiment Mode 12, is described.

  FIG. 16 illustrates a configuration of a reflective liquid crystal display device having a transistor (hereinafter referred to as an amorphous TFT) using an amorphous semiconductor film as a switching element.

  The pixel portion 405 is provided with a switching TFT 733 made of an amorphous TFT. The amorphous TFT can be formed by a known method. For example, in the case of a channel etch type, a gate electrode is formed over the base film 702, and the gate electrode is covered to form a gate insulating film, an amorphous semiconductor film, An n-type semiconductor film, a source electrode, and a drain electrode are formed. An opening is formed in the n-type semiconductor film using the source electrode and the drain electrode. At this time, part of the amorphous semiconductor film is also removed, so that it is called a channel etch type. Thereafter, a protective film 707 can be formed to form an amorphous TFT. An amorphous TFT also has a channel protection type, and a protective film is provided so that an amorphous semiconductor film is not removed when an opening is formed in an n-type semiconductor film using a source electrode and a drain electrode. Other configurations can be the same as those of the channel etch type.

  Then, an alignment film 708 is formed as in FIG. 15, and a rubbing process is performed. This rubbing process may not be performed depending on the liquid crystal mode.

  In addition, a counter substrate 720 is prepared similarly to FIG. A reflective liquid crystal display device can be formed by sealing liquid crystal 711 between them.

  On the counter substrate 720 side, a retardation plate 716, a polarizing plate 717 that is a stacked polarizing plate, and a polarizing plate 718 are provided in this order from the substrate side. The stacked polarizing plates 717 and 718 and the retardation film 716 can be bonded to the counter substrate 720 in a state of being bonded to each other. At this time, the stacked polarizing plates 717 and 718 are bonded so as to be in a parallel Nicol state.

  Further, the extinction coefficients of the polarizing plates 717 and 718 are different. Alternatively, the wavelength distribution of the extinction coefficient of the polarizing plates 717 and 718 may be varied.

  FIG. 16 shows an example in which two polarizing plates are laminated on one substrate, but three or more polarizing plates may be laminated.

  By having the laminated polarizing plates, the contrast ratio can be increased. In addition, a display device with higher black luminance can be provided by the retardation plate.

  In this manner, when an amorphous TFT is used as the switching TFT 733 to form a liquid crystal display device, an IC 421 formed from a silicon wafer can be mounted as a driver in the driver circuit portion 408 in consideration of operation performance. it can. For example, a signal for controlling the switching TFT 733 can be supplied by connecting a wiring included in the IC 421 and a wiring connected to the switching TFT 733 using an anisotropic conductor including the conductive fine particles 422. . Note that the IC mounting method is not limited to this, and the IC can be mounted by a wire bonding method.

  Still further, a control circuit can be connected through the connection terminal 710. At this time, an anisotropic conductive film including conductive fine particles 422 can be used to connect to the connection terminal 710.

  Other configurations are the same as those in FIG.

  Note that this embodiment mode can be combined with Embodiment Modes 11 to 12 if necessary.

  Further, this embodiment can be implemented in combination with any of the other embodiments and examples in this specification as needed.

[Embodiment 14]
In this embodiment, a reflective liquid crystal display device having a structure different from those of Embodiments 11 to 13 is described with reference to FIGS. 17A to 17B, FIG. 18, and FIG. To do.

  However, the same reference numerals as those in FIGS. 14A to 14B, 15 and 16 denote the same components, and only different components will be described.

  In the reflective liquid crystal display device in FIGS. 17A and 17B, a layer 800 having a liquid crystal element is sandwiched between a first substrate 801 and a second substrate 802 which are arranged to face each other. ing.

  On the outside of the substrate 801, that is, the side not in contact with the layer 800 having a liquid crystal element, a retardation plate and a stacked polarizing plate are sequentially provided. On the first substrate 801 side, a retardation plate 821, a first polarizing plate 803, and a second polarizing plate 804 are sequentially provided. The absorption axis 851 of the first polarizing plate 803 and the absorption axis 852 of the second polarizing plate 804 are stacked in parallel. The slow axis of the phase difference plate 821 is indicated by 853. External light passes through the second polarizing plate 804, the second polarizing plate 803, the retardation plate 821, and the substrate 801 and enters the layer 800 having a liquid crystal element. Display is performed by being reflected by a reflective material provided on the second substrate 802.

  The extinction coefficients of the first polarizing plate 803 and the second polarizing plate 804 are different. Alternatively, the wavelength distribution of the extinction coefficient between the first polarizing plate 803 and the second polarizing plate 804 may be different.

  Specific structures of the reflective liquid crystal display device of this embodiment are shown in FIGS. In FIG. 18, the description of FIG. 15 is used in FIGS. 15 and 19, and the same components are denoted by the same reference numerals.

  FIG. 18 shows a reflective liquid crystal display device using a TFT having a crystalline semiconductor film as a switching element, and FIG. 19 shows a reflective liquid crystal display device using a TFT having an amorphous semiconductor film as a switching element.

  In FIG. 18, the pixel electrode 811 connected to the switching TFT 703 is formed of a light-transmitting conductive material. As such a light-transmitting conductive material, a material similar to that of the counter electrode 523 in Embodiment 12 can be used.

  The counter electrode 812 is formed using a reflective conductive material. As such a reflective conductive material, a material similar to that of the pixel electrode 706 of Embodiment 2 can be used.

  The color filter 722 and the black matrix 724 are provided on the surface opposite to the surface on which the TFT of the substrate 701 is formed. Further, a retardation plate 825, a first polarizing plate 826, and a second polarizing plate 827 are stacked.

  The extinction coefficients of the first polarizing plate 826 and the second polarizing plate 827 are different. Alternatively, the wavelength distribution of the extinction coefficient between the first polarizing plate 826 and the second polarizing plate 827 may be different.

  In FIG. 19, the pixel electrode 831 connected to the switching TFT 733 is formed of a light-transmitting conductive material. As such a light-transmitting conductive material, a material similar to that of the counter electrode 723 in Embodiment 12 can be used.

  The counter electrode 832 is formed using a reflective conductive material. As such a reflective conductive material, a material similar to that of the pixel electrode 706 of Embodiment 12 can be used.

  The color filter 722 and the black matrix 724 are provided on the surface opposite to the surface on which the TFT of the substrate 701 is formed. Further, a retardation plate 841, a first polarizing plate 842, and a second polarizing plate 843 are stacked.

  Further, the extinction coefficients of the polarizing plates 842 and 843 are different. Alternatively, the wavelength distribution of the extinction coefficient of the polarizing plates 842 and 843 may be varied.

  17A to 17B, FIG. 18 and FIG. 19 show an example in which two polarizing plates are stacked on one substrate, but three or more may be stacked. .

  Note that in this embodiment mode, a stacked polarizing plate is used as a stacked polarizer (see FIG. 2A), but the configuration shown in FIGS. 2B to 2C is used. Also good.

  Note that this embodiment can be combined with Embodiments 11 to 13 if necessary.

  Further, this embodiment can be implemented in combination with any of the other embodiments and examples in this specification as needed.

[Embodiment 15]
In this embodiment, operations of circuits and the like included in the liquid crystal display devices of Embodiments 4 to 14 will be described.

  20A to 20C and FIG. 21 are system block diagrams of the pixel portion 405 and the driver circuit portion 408 of the liquid crystal display device.

  The pixel portion 405 includes a plurality of pixels, and a switching element is provided in an intersection region between the signal line 412 serving as each pixel and the scanning line 410. 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 408 includes a control circuit 402, a signal line driver circuit 403, and a scanning line driver circuit 404. The control circuit 402 has a function of performing gradation control in accordance with display contents of the pixel portion 405. Therefore, the control circuit 402 inputs the generated signal to the signal line driver circuit 403 and the scan line driver circuit 404. When a switching element is selected via the scanning line 410 based on the scanning line driving circuit 404, 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 403 via the signal line.

  Further, for the transmissive liquid crystal display devices shown in FIGS. 6, 7, 9, and 10, the control circuit 402 shown in FIG. 20A generates a signal for controlling the power supplied to the illumination unit 406. The signal is input to the power source 407 of the illumination unit 406. The backlight unit shown in FIGS. 11 to 13 can be used as the illumination means. 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.

  On the other hand, the reflective liquid crystal display devices shown in FIGS. 15, 16, 18, and 19 do not require an illuminating means and a power source, so the configuration shown in FIG.

  As illustrated in FIG. 20B, the scan line driver circuit 404 includes circuits that function as a shift register 441, a level shifter 442, and a buffer 443. Signals such as a gate start pulse (GSP) and a gate clock signal (GCK) are input to the shift register 441. Note that the scan line driver circuit of the present invention is not limited to the structure shown in FIG.

  20C, the signal line driver circuit 403 includes circuits that function as a shift register 431, a first latch 432, a second latch 433, a level shifter 434, and a buffer 435. A circuit functioning as the buffer 435 is a circuit having a function of amplifying a weak signal and includes an operational amplifier and the like. A signal such as a start pulse (SSP) is input to the level shifter 434, and data (DATA) such as a video signal generated based on the video signal 401 is input to the first latch 432. A latch (LAT) signal can be temporarily held in the second latch 433 and is input to the pixel portion 405 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 403, the scan line driver circuit 404, and the pixel portion 405 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 applied to the semiconductor element. 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 403 and the scan line driver circuit 404 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 the above embodiment mode).

  In such a liquid crystal display device, the contrast ratio can be increased by providing stacked polarizers. In other words, the laminated polarizer can increase the contrast ratio between the light from the illumination means controlled by the control circuit and the reflected light.

  Further, this embodiment can be implemented in combination with any of the other embodiments and examples in this specification as needed.

[Embodiment 16]
In this embodiment mode, a concept of a display device including the light-emitting element of the present invention will be described.

  In the configuration of the present invention, as a light emitting element, there are an element using electroluminescence (electroluminescence element), an element using plasma, and an element using field emission. An electroluminescence element can be distinguished from an organic EL element or an inorganic EL element depending on a material to be applied. A display device having such a light-emitting element is also referred to as a light-emitting device. In this embodiment mode, an electroluminescence element is used as the light-emitting element.

  As shown in FIG. 22, a layer 1100 having an electroluminescent element is sandwiched between a first substrate 1101 and a second substrate 1102 which are arranged to face each other. 22A is a cross-sectional view of the display device of this embodiment mode, and FIG. 22B is a perspective view of the display device of this embodiment mode.

  In FIG. 22B, light emitted from the electroluminescent element can be emitted from the first substrate 1101 side and the second substrate 1102 side (in the direction of the dotted arrow). Light-transmitting substrates are used as the first substrate 1101 and the second substrate 1102. As the light-transmitting substrate, 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 plastics typified by polyethylene-terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), polycarbonate (PC), or flexible synthetic resin such as acrylic is applied. can do.

  Stacked polarizers are provided on the outer sides of the first substrate 1101 and the second substrate 1102, that is, on the side not in contact with the layer 1100 having an electroluminescent element. Light emitted from the electroluminescence element is linearly polarized by the polarizer. That is, the stacked polarizers can be described as stacked linear polarizers. The laminated polarizer refers to a state in which two or more polarizers are laminated. In this embodiment mode, a display device in which two polarizers are stacked is illustrated, and the two stacked polarizers are stacked in contact with each other as illustrated in FIG.

  Embodiment 2 can be used for the structure of the stacked layers of the polarizers. In this embodiment mode, the structure illustrated in FIG. 2A is used as the stacked polarizer, but the structure illustrated in FIG. 2B or 2C may be used.

  22A to 22B show an example in which two polarizers are stacked, three or more may be stacked.

  A first polarizing plate 1111 and a second polarizing plate 1112 are sequentially provided on the outside of the first substrate 1101 as the stacked polarizing plates 1131. The absorption axis 1151 of the first polarizing plate 1111 and the absorption axis 1152 of the second polarizing plate 1112 are arranged in parallel. That is, the first polarizing plate 1111 and the second polarizing plate 1112, that is, the stacked polarizing plates 1131 are arranged in parallel Nicols.

  In addition, a third polarizing plate 1121 and a fourth polarizing plate 1122 are provided in this order as the stacked polarizing plates 1132 outside the second substrate 1102. The absorption axis 1153 of the third polarizing plate 1121 and the absorption axis 1154 of the fourth polarizing plate 1122 are arranged in parallel. That is, the third polarizing plate 1121 and the fourth polarizing plate 1122, that is, the stacked polarizing plates 1132 are arranged in parallel Nicols.

  Then, the absorption axis 1151 (and 1152) of the laminated polarizing plate 1131 provided on the first substrate 1101 and the absorption axis 1153 of the laminated polarizing plate 1132 provided on the second substrate 1102 (and 1154) is orthogonal. That is, the stacked polarizing plates 1131 and the stacked polarizing plates 1132, that is, the stacked polarizing plates facing each other, are arranged so as to form a crossed Nicol.

  These polarizing plates 1111, 1112, 1121, 1122 can be formed from a known material, for example, an adhesive surface from the substrate side, a mixed layer of TAC (triacetylcellulose), PVA (polyvinyl alcohol) and dichroic dye, A configuration in which TACs are sequentially stacked can be used. Dichroic pigments include iodine and dichroic organic dyes. Moreover, a polarizing plate may be called a polarizing film from the shape.

  Note that, due to the characteristics of the polarizing plate, there is a transmission axis in a direction orthogonal to the absorption axis. Therefore, even when the transmission axes are parallel to each other, it can be called parallel Nicol.

  By laminating so that the transmission axes of the laminated polarizing plates are parallel Nicols, light leakage in the absorption axis direction can be reduced. And it arrange | positions so that the polarizing plates which oppose may become cross Nicole. By having such a laminated polarizing plate, light leakage can be reduced as compared with a configuration in which the polarizing plate single layers are simply arranged in crossed Nicols. For this reason, the contrast ratio of the display device can be increased.

  Further, the extinction coefficients of the polarizing plate 1111 and the polarizing plate 1112 are different, and the extinction coefficients of the polarizing plate 1121 and the polarizing plate 1122 are different. Alternatively, the wavelength distribution of the extinction coefficient between the polarizing plate 1111 and the polarizing plate 1112 may be different, or the wavelength distribution of the extinction coefficient between the polarizing plate 1121 and the polarizing plate 1122 may be different.

  Note that this embodiment can be implemented freely combining with any of the other embodiments and examples in this specification, if necessary.

[Embodiment 17]
In this embodiment mode, FIG. 23 is used to illustrate a cross-sectional view of a display device of the present invention.

  A thin film transistor is formed over a substrate having an insulating surface (hereinafter referred to as an insulating substrate) 1201 with an insulating layer interposed therebetween. A thin film transistor (also referred to as a (Thin Film Transistor) TFT) includes a semiconductor layer processed into a predetermined shape, a gate insulating layer covering the semiconductor layer, a gate electrode provided on the semiconductor layer through the gate insulating layer, A source electrode or a drain electrode connected to the impurity layer.

  The material used for the semiconductor layer is a semiconductor material containing silicon, and the crystalline state may be any of an amorphous state, a microcrystalline state, and a crystalline state. For the insulating layer typified by the gate insulating film, an inorganic material is preferably used, and silicon nitride or silicon oxide can be used. The gate electrode, the source electrode, or the drain electrode may be formed using a conductive material, and includes tungsten, tantalum, aluminum, titanium, silver, gold, molybdenum, copper, and the like.

  The display device in this embodiment can be broadly divided into a pixel portion 1215 and a driver circuit portion 1218. A thin film transistor 1203 provided in the pixel portion 1215 is a switching element, and a thin film transistor 1204 provided in the driver circuit portion 1218 is a CMOS. Used as a circuit. In order to be used as a CMOS circuit, it is composed of a P-channel TFT and an N-channel TFT. The thin film transistor 1203 can be controlled by a CMOS circuit provided in the driver circuit portion 1218.

  Note that although a top gate TFT is shown as a thin film transistor in FIG. 23, a bottom gate TFT may be used.

  An insulating layer 1205 having a stacked structure or a single layer structure is formed so as to cover the thin film transistors 1203 and 1204. The insulating layer 1205 can be formed of an inorganic material or an organic material.

  As the inorganic material, silicon nitride or silicon oxide can be used. As the organic material, polyimide, acrylic, polyamide, polyimide amide, resist, benzocyclobutene, siloxane, or polysilazane can be used. Siloxane has a skeletal structure composed of a bond of silicon (Si) and oxygen (O), and an organic group containing at least hydrogen (such as an alkyl group or aromatic hydrocarbon) is used as a substituent. 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. Polysilazane is formed using a liquid material containing a polymer material having a bond of silicon (Si) and nitrogen (N) as a starting material. When formed using an inorganic material, the surface is in a state of following the unevenness on the lower side. When formed using an organic material, the surface is flattened. For example, in the case where flatness is required for the insulating layer 1205, an organic material may be used. In addition, even if it is an inorganic material, flatness can be provided by thickening.

  The source electrode or the drain electrode is manufactured by forming a conductive layer in an opening provided in the insulating layer 1205 or the like. At this time, a conductive layer functioning as a wiring over the insulating layer 1205 can be formed. The capacitor 1214 can be formed using the conductive layer of the gate electrode, the insulating layer 1205, and the conductive layer of the source or drain electrode.

  Then, a first electrode 1206 connected to any one of the source electrode and the drain electrode is formed. The first electrode 1206 is formed using a light-transmitting material. Examples of the light-transmitting material include indium tin oxide (Indium Tin Oxide (ITO)), zinc oxide (ZnO), indium zinc oxide (Indium Zinc Oxide (IZO)), and zinc oxide added with gallium (GZO). Can be mentioned. Alkali metals such as Li and Cs, and alkaline earth metals such as Mg, Ca, and Sr, alloys containing these (Mg: Ag, Al: Li, Mg: In, etc.), and compounds thereof (calcium fluoride, In addition to calcium nitride), even non-transparent materials such as rare earth metals such as Yb and Er can be made translucent by having a very thin film thickness. May be used for the first electrode 1206.

  An insulating layer 1210 is formed so as to cover an end portion of the first electrode 1206. The insulating layer 1210 can be formed in a manner similar to that of the insulating layer 1205. In order to cover the end portion of the first electrode 1206, an opening is provided in the insulating layer 1210. The end face of the opening may have a taper shape, and a layer formed thereafter can be prevented from being disconnected. For example, when a non-photosensitive resin or a photosensitive resin is used for the insulating layer 1210, the side surface of the opening can be tapered depending on the exposure conditions.

  After that, an electroluminescent layer 1207 is formed in the opening of the insulating layer 1210. The electroluminescent layer has a layer having each function, specifically, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer. Moreover, the boundary of each layer is not necessarily clear, and some of them may be mixed.

As a specific example of the material for forming the light emitting layer, when red light emission is desired, 4-dicyanomethylene-2-isopropyl-6- [2- (1,1,7,7-tetra Methyljulolidin-9-yl) ethenyl] -4H-pyran (abbreviation: DCJTI), 4-dicyanomethylene-2-methyl-6- [2- (1,1,7,7-tetramethyljulolidine-9- Yl) ethenyl] -4H-pyran (abbreviation: DCJT), 4-dicyanomethylene-2-tert-butyl-6- [2- (1,1,7,7-tetramethyljulolidin-9-yl) ethenyl] -4H-pyran (abbreviation: DCJTB), periflanthene, 2,5-dicyano-1,4-bis [2- (10-methoxy-1,1,7,7-tetramethyljulolidin-9-yl) ethenyl] Benze , Bis [2,3-bis (4-fluorophenyl) Kinokisarinaito] iridium (acetylacetonate) (abbreviation: Ir [Fdpq] 2 acac), or the like can be used. However, the present invention is not limited to these materials, and a substance exhibiting light emission having an emission spectrum peak from 600 nm to 700 nm can be used.

When green light emission is desired, N, N′-dimethylquinacridone (abbreviation: DMQd), coumarin 6, coumarin 545T, tris (8-quinolinolato) aluminum (abbreviation: Alq 3 ), or the like is used for the light emitting layer. Can do. However, the present invention is not limited to these materials, and a substance exhibiting light emission having an emission spectrum peak from 500 nm to 600 nm can be used.

  In order to obtain blue light emission, 9,10-bis (2-naphthyl) -tert-butylanthracene (abbreviation: t-BuDNA), 9,9′-bianthryl, 9,10-diphenyl is used in the light-emitting layer. Anthracene (abbreviation: DPA), 9,10-bis (2-naphthyl) anthracene (abbreviation: DNA), bis (2-methyl-8-quinolinolato) -4-phenylphenolato-gallium (abbreviation: BGaq), bis ( 2-methyl-8-quinolinolato) -4-phenylphenolato-aluminum (abbreviation: BAlq) or the like can be used. However, the present invention is not limited to these materials, and a substance exhibiting light emission having an emission spectrum peak from 400 nm to 500 nm can be used.

When white light emission is desired, TPD (aromatic diamine), 3- (4-tert-butylphenyl) -4-phenyl-5- (4-biphenylyl) -1,2,4-triazole (abbreviation) : TAZ), tris (8-quinolinolato) aluminum (abbreviation: Alq 3), can be used a configuration in which laminated by the Alq 3, Alq 3 doped with Nile red which is a red light emitting pigment deposition method.

  After that, the second electrode 1208 is formed. The second electrode 1208 can be formed in a manner similar to that of the first electrode 1206. A light-emitting element 1209 including the first electrode 1206, the electroluminescent layer 1207, and the second electrode 1208 can be formed.

  At this time, since the first electrode 1206 and the second electrode 1208 have a light-transmitting property, light can be emitted from the electroluminescent layer 1207 in both directions. Such a display device capable of emitting light in both directions can be referred to as a dual emission type display device.

  After that, the insulating substrate 1201 and the counter substrate 1220 are attached to each other with a sealing material 1228. In this embodiment mode, the sealing material 1228 is provided over part of the driver circuit portion 1218; thus, the frame can be narrowed. Needless to say, the arrangement of the sealing material 1228 is not limited to this, and the sealing material 1228 may be provided outside the driver circuit portion 1218.

  The space formed by the bonding is filled with an inert gas such as nitrogen, or is filled with a resin material having a light-transmitting property and a high hygroscopic property. As a result, intrusion of moisture or oxygen that is a cause of deterioration of the light-emitting element 1209 can be prevented. In order to maintain a distance between the insulating substrate 1201 and the counter substrate 1220, a spacer may be provided or the spacer may be hygroscopic. The spacer has a spherical or columnar shape.

  The counter substrate 1220 can be provided with a color filter or a black matrix. The color filter enables full color display even when a monochromatic light emitting layer, for example, a white light emitting layer is used. Even when each of the RGB light emitting layers is used, by providing a color filter, the wavelength of emitted light can be controlled and a beautiful display can be provided. Further, the black matrix can reduce reflection of external light due to wiring or the like.

  After that, the first polarizing plate 1216 and the second polarizing plate 1217 are sequentially stacked on the outside of the insulating substrate 1201 as the stacked polarizing plate 1219, and the third polarizing plate 1229 is stacked on the outside of the counter substrate 1220 in order. The polarizing plate 1226 and the fourth polarizing plate 1227 are provided. That is, the stacked polarizing plates 1219 and 1229 are provided outside the insulating substrate 1201 and the counter substrate 1220, respectively.

  At this time, the polarizing plates 1216 and 1217 are bonded so as to be in a parallel Nicol state. The polarizing plates 1226 and 1227 are also bonded so as to be in a parallel Nicol state.

  Further, the stacked polarizing plates 1219 and 1229 are arranged so as to be in a crossed Nicols state.

  As a result, the black display can be darkened, that is, the black luminance can be increased and the contrast ratio can be increased.

  In this embodiment mode, a structure in which the polarizing plates illustrated in FIG. 2A are stacked is used as the polarizer. Needless to say, the stacked polarizers illustrated in FIGS. 2B and 2C may be used. .

  Further, the extinction coefficients of the polarizing plate 1216 and the polarizing plate 1217 are different, and the extinction coefficients of the polarizing plate 1226 and the polarizing plate 1227 are different. Alternatively, the wavelength distribution of the extinction coefficient between the polarizing plate 1216 and the polarizing plate 1217 may be different, or the wavelength distribution of the extinction coefficient between the polarizing plate 1226 and the polarizing plate 1227 may be different.

  FIG. 23 shows an example in which two polarizing plates are stacked on one substrate, but three or more polarizing plates may be stacked.

  In this embodiment mode, the driving circuit portion is also formed over the insulating substrate 1201. However, the driving circuit portion may be an IC circuit formed from a silicon wafer. In that case, a video signal or the like from the IC circuit can be input to the switching thin film transistor 1203 through a connection terminal or the like.

  Note that although an active display device is described in this embodiment mode, a stacked polarizing plate can be provided even in a passive display device. As a result, the contrast ratio can be increased.

  Note that this embodiment can be implemented freely combining with any of the other embodiments and examples in this specification.

[Embodiment 18]
In this embodiment mode, the concept of the display device of the present invention will be described. In this embodiment mode, description is made using an electroluminescence element as a light-emitting element.

  As shown in FIG. 24, a layer 1300 having an electroluminescent element is sandwiched between a first substrate 1301 and a second substrate 1302 which are arranged to face each other. Light emitted from the electroluminescent element can be emitted from the first substrate 1301 side and the second substrate 1302 side (in the direction of the dotted arrow).

  A light-transmitting substrate is used as the first substrate 1301 and the second substrate 1302. As the light-transmitting substrate, 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 plastics typified by polyethylene-terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), polycarbonate (PC), or flexible synthetic resin such as acrylic is applied. can do.

  A phase difference plate and a stacked polarizer are provided on the outside of the first substrate 1301 and the second substrate 1302, that is, the side not in contact with the layer 1300 having an electroluminescent element. Note that in this embodiment, as the stacked polarizers, a structure in which a polarizing plate having one polarizing film illustrated in FIG. 2A is stacked is used. Of course, it goes without saying that the configuration shown in FIG. 2B or 2C may be used. The light is circularly polarized by the retardation plate and linearly polarized by the polarizing plate. That is, the stacked polarizers can be described as stacked linear polarizers. The laminated polarizer refers to a state in which two or more polarizers are laminated.

  On the outside of the first substrate 1301, a first retardation plate 1313, a first polarizing plate 1311 that is a stacked polarizing plate 1315, and a second polarizing plate 1312 are sequentially provided. In the present embodiment, quarter wave plates are used as the phase difference plate 1313 and a phase difference plate 1323 described later.

In this way, the retardation plate and the laminated polarizing plates are combined and also referred to as a circularly polarizing plate having a laminated polarizing plate (linear polarizing plate). The absorption axis 1335 of the first polarizing plate 1311 and the absorption axis 1336 of the second polarizing plate 1312 are arranged in parallel. That is, the first polarizing plate 1311 and the second polarizing plate 1312, that is, the stacked polarizing plates 1315 are arranged in parallel Nicols.

  Further, the slow axis 1331 of the retardation film 1313 is disposed so as to be shifted from the absorption axis 1335 of the first polarizing plate 1311 and the absorption axis 1336 of the second polarizing plate 1312 by 45 °.

  FIG. 25A shows a deviation angle between the absorption axis 1335 (and 1336) and the slow axis 1331. FIG. The slow axis 1331 makes an angle of 135 °, the absorption axis 1335 (and 1336) makes an angle of 90 °, and these are shifted by 45 °.

  In addition, a second retardation plate 1323 and a third polarizing plate 1321 and a fourth polarizing plate 1322 are provided as the stacked polarizing plates 1325 in this order on the outside of the second substrate 1302. The retardation plate and the laminated polarizing plate are also referred to as a circularly polarizing plate having the laminated polarizing plates. The absorption axis 1337 of the third polarizing plate 1321 and the absorption axis 1338 of the fourth polarizing plate 1322 are arranged in parallel. That is, the third polarizing plate 1321 and the fourth polarizing plate 1322, that is, the stacked polarizing plates 1325 are arranged in parallel Nicols.

  The slow axis 1332 of the phase difference plate 1323 is arranged to be shifted by 45 ° from the absorption axis 1337 of the third polarizing plate 1321 and the absorption axis 1338 of the fourth polarizing plate 1322.

  FIG. 25B shows the deviation angle between the absorption axis 1337 (and 1338) and the slow axis 1332. The slow axis 1332 forms 45 °, the absorption axis 1337 (and 1338) forms 0 °, and these are shifted by 45 °. That is, the slow axis 1331 of the first retardation plate 1313 is arranged to be shifted by 45 ° with respect to the absorption axis 1335 of the first linearly polarizing plate 1311 (and the absorption axis 1336 of the second linearly polarizing plate 1312). The slow axis 1332 of the second retardation film 1323 is arranged to be shifted by 45 ° with respect to the absorption axis 1337 of the third linearly polarizing plate 1321 (and the absorption axis 1338 of the fourth linearly polarizing plate 1322).

  Then, the absorption axis 1335 (and 1336) of the stacked polarizing plate 1315 provided on the first substrate 1301, and the absorption axis 1337 of the stacked polarizing plate 1325 provided on the second substrate 1302 (and 1338) is orthogonal. That is, the stacked polarizing plates 1315 and the stacked polarizing plates 1325, that is, the opposing polarizing plates are arranged so as to form crossed Nicols.

  In FIG. 25C, the absorption axis 1335 and the slow axis 1331 are indicated by solid lines, the absorption axis 1337 and the slow axis 1332 are indicated by dotted lines, and a state in which these are overlapped is shown. FIG. 2C shows that the absorption axis 1335 and the absorption axis 1337 have a crossed Nicols state, and the slow axis 1331 and the slow axis 1332 have a crossed Nicols state.

  In this specification, when describing the shift between the absorption axis and the slow axis, the shift between the absorption axes, and the shift between the slow axes, the above angle is assumed, but if similar effects can be expressed, It may be slightly deviated from the angle.

  These polarizing plates 1311, 1312, 1321, 1322 can be formed from a known material, for example, an adhesive surface from the substrate side, a mixed layer of TAC (triacetylcellulose), PVA (polyvinyl alcohol) and dichroic dye, A configuration in which TACs are sequentially stacked can be used. Dichroic pigments include iodine and dichroic organic dyes. Moreover, a polarizing plate may be called a polarizing film from the shape.

Note that, due to the characteristics of the polarizing plate, there is a transmission axis in a direction orthogonal to the absorption axis. Therefore, even when the transmission axes are parallel to each other, it can be called parallel Nicol.

  Further, the extinction coefficients of the polarizing plate 1311 and the polarizing plate 1312 are different, and the extinction coefficients of the polarizing plate 1321 and the polarizing plate 1322 are different. Or the wavelength distribution of the extinction coefficient of the polarizing plate 1311 and the polarizing plate 1312 may differ, and the wavelength distribution of the extinction coefficient of the polarizing plate 1321 and the polarizing plate 1322 may differ.

  FIG. 24 shows an example in which two polarizing plates are laminated on one substrate, but three or more polarizing plates may be laminated.

  Further, due to the characteristics of the phase difference plate, there is a fast axis in a direction orthogonal to the slow axis. Therefore, the arrangement with the polarizing plate can be determined using not only the slow axis but also the fast axis. In this embodiment, since the absorption axis and the slow axis are arranged so as to be shifted by 45 °, in other words, the absorption axis and the fast axis are arranged so as to be shifted by 135 °.

  In addition, the circularly polarizing plate includes a circularly polarizing plate having a wide band that can widen the wavelength range of 90 degrees of phase difference by overlapping several retardation plates. In this case as well, the first substrate 1301 is used. The slow axes of the retardation plates arranged outside the second retardation plate and the retardation plates arranged outside the second substrate 1302 are arranged at 90 degrees between the slow axes of the retardation plates. The absorption axes may be in a crossed Nicols arrangement.

  In this specification, when the shift between the absorption axes, the shift between the absorption axis and the slow axis, and the shift between the slow axes are described, the above angle is assumed, but the same effect can be expressed. , It may deviate somewhat from that angle.

  By laminating so that the absorption axes of the laminated polarizing plates are parallel Nicols, light leakage in the absorption axis direction can be reduced. And it arrange | positions so that the polarizing plates which oppose may become cross Nicole. By providing a circularly polarizing plate having such a polarizing plate, light leakage can be reduced as compared with a circularly polarizing plate arranged so that single polarizing plates are crossed Nicols. For this reason, the contrast ratio of the display device can be increased.

[Embodiment 19]
In this embodiment mode, FIG. 26 is used to illustrate a cross-sectional view of a display device of the present invention.

  Note that in the display device illustrated in FIG. 26, the same components as those in FIG. 23 are denoted by the same reference numerals, and the description of FIG.

  A thin film transistor is formed over a substrate having an insulating surface (hereinafter referred to as an insulating substrate) 1201 with an insulating layer interposed therebetween. A thin film transistor (also referred to as a (Thin Film Transistor) TFT) includes a semiconductor layer processed into a predetermined shape, a gate insulating layer covering the semiconductor layer, a gate electrode provided on the semiconductor layer through the gate insulating layer, A source electrode or a drain electrode connected to the impurity layer. The material used for the semiconductor layer is a semiconductor material containing silicon, and the crystalline state may be any of an amorphous state, a microcrystalline state, and a crystalline state. For the insulating layer typified by the gate insulating film, an inorganic material is preferably used, and silicon nitride or silicon oxide can be used. The gate electrode, the source electrode, or the drain electrode may be formed using a conductive material, and includes tungsten, tantalum, aluminum, titanium, silver, gold, molybdenum, copper, and the like.

  The display device can be roughly divided into a pixel portion 1215 and a driver circuit portion 1218. A thin film transistor 1203 provided in the pixel portion 1215 is used as a switching element, and a thin film transistor 1204 provided in the driver circuit portion is used as a CMOS circuit. In order to be used as a CMOS circuit, it is composed of a P-channel TFT and an N-channel TFT. The thin film transistor 1203 can be controlled by a CMOS circuit provided in the driver circuit portion 1218.

  In FIG. 26, a top gate TFT is shown as a thin film transistor, but a bottom gate TFT may be used.

  An insulating layer 1205 having a stacked structure or a single layer structure is formed so as to cover the thin film transistors 1203 and 1204. The insulating layer 1205 can be formed of an inorganic material or an organic material. As the inorganic material, silicon nitride or silicon oxide can be used. As the organic material, polyimide, acrylic, polyamide, polyimide amide, resist, benzocyclobutene, siloxane, or polysilazane can be used. Siloxane has a skeletal structure composed of a bond of silicon (Si) and oxygen (O), and an organic group containing at least hydrogen (such as an alkyl group or aromatic hydrocarbon) is used as a substituent. 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. Polysilazane is formed using a liquid material containing a polymer material having a bond of silicon (Si) and nitrogen (N) as a starting material. When formed using an inorganic material, the surface is in a state of following the unevenness on the lower side. When formed using an organic material, the surface is flattened. For example, in the case where flatness is required for the insulating layer 1205, an organic material may be used. In addition, even if it is an inorganic material, flatness can be provided by thickening.

  The source electrode or the drain electrode is manufactured by forming a conductive layer in an opening provided in the insulating layer 1205 or the like. At this time, a conductive layer functioning as a wiring over the insulating layer 1205 can be formed. The capacitor 1214 can be formed using the conductive layer of the gate electrode, the insulating layer 1205, and the conductive layer of the source or drain electrode.

Then, a first electrode 1206 connected to any one of the source electrode and the drain electrode is formed. The first electrode 1206 is formed using a light-transmitting material. Examples of the light-transmitting material include indium tin oxide ((Indium Tin Oxide (ITO)), zinc oxide (ZnO), indium zinc oxide (Indium Zinc Oxide (IZO)), zinc oxide added with gallium (GZO), and the like. Alkali metals such as Li and Cs, and alkaline earth metals such as Mg, Ca, and Sr, alloys containing these (Mg: Ag, Al: Li, Mg: In, etc.), and compounds thereof ( In addition to CaF 2 and calcium nitride), even non-transparent materials such as rare earth metals such as Yb and Er can be made translucent by having a very thin film thickness. A light-sensitive material may be used for the first electrode 1206.

  An insulating layer 1210 is formed so as to cover an end portion of the first electrode 1206. The insulating layer 1210 can be formed in a manner similar to that of the insulating layer 1205. In order to cover the end portion of the first electrode 1206, an opening is provided in the insulating layer 1210. The end face of the opening may have a taper shape, and a layer formed thereafter can be prevented from being disconnected. For example, when a non-photosensitive resin or a photosensitive resin is used for the insulating layer 1210, the side surface of the opening can be tapered depending on the exposure conditions.

  After that, an electroluminescent layer 1207 is formed in the opening of the insulating layer 1210. The electroluminescent layer 1207 has a layer having each function, specifically, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer. Moreover, the boundary of each layer is not necessarily clear, and some of them may be mixed.

As a specific example of the material for forming the light emitting layer, when red light emission is desired, 4-dicyanomethylene-2-isopropyl-6- [2- (1,1,7,7-tetra Methyljulolidin-9-yl) ethenyl] -4H-pyran (abbreviation: DCJTI), 4-dicyanomethylene-2-methyl-6- [2- (1,1,7,7-tetramethyljulolidine-9- Yl) ethenyl] -4H-pyran (abbreviation: DCJT), 4-dicyanomethylene-2-tert-butyl-6- [2- (1,1,7,7-tetramethyljulolidin-9-yl) ethenyl] -4H-pyran (abbreviation: DCJTB), periflanthene, 2,5-dicyano-1,4-bis [2- (10-methoxy-1,1,7,7-tetramethyljulolidin-9-yl) ethenyl] Benze , Bis [2,3-bis (4-fluorophenyl) Kinokisarinaito] iridium (acetylacetonate) (abbreviation: Ir [Fdpq] 2 acac), or the like can be used. However, the present invention is not limited to these materials, and a substance exhibiting light emission having an emission spectrum peak from 600 nm to 700 nm can be used.

When green light emission is desired, N, N′-dimethylquinacridone (abbreviation: DMQd), coumarin 6, coumarin 545T, tris (8-quinolinolato) aluminum (abbreviation: Alq 3 ), or the like is used for the light emitting layer. Can do. However, the present invention is not limited to these materials, and a substance exhibiting light emission having an emission spectrum peak from 500 nm to 600 nm can be used.

  In order to obtain blue light emission, 9,10-bis (2-naphthyl) -tert-butylanthracene (abbreviation: t-BuDNA), 9,9′-bianthryl, 9,10-diphenyl is used in the light-emitting layer. Anthracene (abbreviation: DPA), 9,10-bis (2-naphthyl) anthracene (abbreviation: DNA), bis (2-methyl-8-quinolinolato) -4-phenylphenolato-gallium (abbreviation: BGaq), bis ( 2-methyl-8-quinolinolato) -4-phenylphenolato-aluminum (abbreviation: BAlq) or the like can be used. However, the present invention is not limited to these materials, and a substance exhibiting light emission having an emission spectrum peak from 400 nm to 500 nm can be used.

When white light emission is desired, TPD (aromatic diamine), 3- (4-tert-butylphenyl) -4-phenyl-5- (4-biphenylyl) -1,2,4-triazole (abbreviation) : TAZ), tris (8-quinolinolato) aluminum (abbreviation: Alq 3), can be used a configuration in which laminated by the Alq 3, Alq 3 doped with Nile red which is a red light emitting pigment deposition method.

  After that, the second electrode 1208 is formed. The second electrode 1208 can be formed in a manner similar to that of the first electrode 1206. A light-emitting element 1209 including the first electrode 1206, the electroluminescent layer 1207, and the second electrode 1208 can be formed.

At this time, since the first electrode 1206 and the second electrode 1208 have a light-transmitting property, light can be emitted from the electroluminescent layer 1207 in both directions. Such a display device capable of emitting light in both directions can be called a dual emission display device.

  After that, the insulating substrate 1201 and the counter substrate 1220 are attached to each other with a sealing material 1228. In this embodiment mode, the sealing material 1228 is provided over part of the driver circuit portion 1218; thus, the frame can be narrowed. Needless to say, the arrangement of the sealing material 1228 is not limited to this, and the sealing material 1228 may be provided outside the driver circuit portion 1218.

  The space formed by the bonding is filled with an inert gas such as nitrogen, or is filled with a resin material having a light-transmitting property and a high hygroscopic property. As a result, intrusion of moisture or oxygen that is a cause of deterioration of the light-emitting element 1209 can be prevented. In order to maintain a distance between the insulating substrate 1201 and the counter substrate 1220, a spacer may be provided or the spacer may be hygroscopic. The spacer has a spherical or columnar shape.

  The counter substrate 1220 can be provided with a color filter or a black matrix. The color filter enables full color display even when a monochromatic light emitting layer, for example, a white light emitting layer is used. Even when each of the RGB light emitting layers is used, by providing a color filter, the wavelength of emitted light can be controlled and a beautiful display can be provided. Further, the black matrix can reduce reflection of external light due to wiring or the like.

  Thereafter, the first retardation plate 1235, the stacked polarizing plate 1219, and the first polarizing plate 1216, the second polarizing plate 1217, and the counter substrate 1220 are sequentially formed outside the insulating substrate 1201 and 1219. A third polarizing plate 1226 and a fourth polarizing plate 1227 are sequentially provided as the retardation plate 1225 and the laminated polarizing plate 1229. That is, a circularly polarizing plate having stacked polarizing plates is provided on the outside of each of the insulating substrate 1201 and the counter substrate 1220.

  At this time, the polarizing plates 1216 and 1217 are bonded so as to be in a parallel Nicol state. The polarizing plates 1226 and 1227 are also bonded so as to be in a parallel Nicol state.

  Further, the stacked polarizing plates 1219 and 1229 are arranged so as to be in a crossed Nicols state.

  As a result, the black display can be darkened, that is, the black luminance can be increased and the contrast ratio can be increased.

  Further, by providing the phase difference plates 1235 and 1225, reflected light from external light with respect to the display device can be suppressed.

  In this embodiment mode, a structure in which the polarizing plates illustrated in FIG. 2A are stacked is used as the polarizer. Needless to say, the stacked polarizers illustrated in FIGS. 2B and 2C may be used. .

  Further, the extinction coefficients of the polarizing plate 1216 and the polarizing plate 1217 are different, and the extinction coefficients of the polarizing plate 1226 and the polarizing plate 1227 are different. Alternatively, the wavelength distribution of the extinction coefficient between the polarizing plate 1216 and the polarizing plate 1217 may be different, or the wavelength distribution of the extinction coefficient between the polarizing plate 1226 and the polarizing plate 1227 may be different.

  FIG. 26 shows an example in which two polarizing plates are laminated on one substrate, but three or more polarizing plates may be laminated.

  In this embodiment mode, the driving circuit portion is also formed over the insulating substrate 1201. However, the driving circuit portion may be an IC circuit formed from a silicon wafer. In that case, a video signal or the like from the IC circuit can be input to the switching TFT 1203 through a connection terminal or the like.

  Note that although an active display device is described in this embodiment mode, a circularly polarizing plate including stacked polarizing plates can be provided even in a passive display device. As a result, the contrast ratio can be increased.

  This embodiment mode can be freely combined with the above embodiment mode, if necessary.

[Embodiment 20]
In this embodiment mode, the concept of the display device of the present invention will be described. In this embodiment mode, description is made using an electroluminescence element as a light-emitting element.

  27A and 27B illustrate a display device in which light from a light-emitting element is emitted above a substrate. As shown in FIGS. 27A and 27B, a layer 1400 including an electroluminescent element as a light-emitting element is sandwiched between a first substrate 1401 and a second substrate 1402 which are arranged to face each other. Has been. Light emitted from the electroluminescence element can be emitted from the first substrate 1401 (in the direction of the dotted arrow).

  A light-transmitting substrate is used as the first substrate 1401. As such a light-transmitting substrate, 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 plastics typified by polyethylene-terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), polycarbonate (PC), or flexible synthetic resin such as acrylic is applied. can do.

  The second substrate 1402 may be a light-transmitting substrate, but light from the layer 1400 including an electroluminescent element is not emitted. As described later, an electrode formed in the layer 1400 having an electroluminescent element is formed using a reflective conductive film, or a reflective material is formed on the entire surface of the second substrate 1402 as described later. Accordingly, light from the layer 1400 including the electroluminescent element may be reflected to the first substrate 1401 side.

  A retardation plate (also referred to as a wavelength plate) and a stacked polarizer are provided outside the surface of the first substrate 1401 where light is emitted. The laminated polarizer can be referred to as a laminated linear polarizer. The laminated polarizer refers to a state in which two or more polarizers are laminated. Note that in this embodiment, as the stacked polarizers, a structure in which a polarizing plate having one polarizing film illustrated in FIG. 2A is stacked is used. Of course, it goes without saying that the configuration shown in FIG. 2B or 2C may be used.

  27A and 27B show only an example in which two polarizing plates are provided, but three or more polarizing plates may be provided.

  In this manner, the retardation plate and the polarizing plate thus laminated (in this embodiment, a quarter-wave plate) are also referred to as a circularly polarizing plate having a laminated polarizing plate (linear polarizing plate).

  The absorption axis 1451 of the first polarizing plate 1403 and the absorption axis 1452 of the second polarizing plate 1404 are arranged in parallel. That is, the first polarizing plate 1403 and the second polarizing plate 1404, that is, the stacked polarizing plates are arranged in parallel Nicols. Further, the slow axis 1453 of the retardation film 1421 is arranged to be shifted by 45 ° from the absorption axis 1451 of the first polarizing plate 1403 and the absorption axis 1452 of the second polarizing plate 1404.

  FIG. 28 shows a deviation angle between the absorption axis 1451 and the slow axis 1453. The slow axis 1453 makes 45 °, the absorption axis 1451 makes 0 °, and these are shifted by 45 °. The absorption axis 1452 is omitted because it is in the same direction as the absorption axis 1451. In other words, the slow axis 1453 of the retardation film 1421 is arranged to be shifted by 45 ° with respect to the absorption axis 1451 of the first linearly polarizing plate 1403.

  These polarizing plates 1403 and 1404 can be formed of a known material. For example, an adhesive surface, a TAC (triacetyl cellulose), a mixed layer of PVA (polyvinyl alcohol) and a dichroic dye, and a TAC are sequentially stacked from the substrate side. Can be used. Dichroic pigments include iodine and dichroic organic dyes. Moreover, a polarizing plate may be called a polarizing film from the shape.

  Note that, due to the characteristics of the polarizing plate, there is a transmission axis in a direction orthogonal to the absorption axis. Therefore, even when the transmission axes are parallel to each other, it can be called parallel Nicol.

  Further, the extinction coefficients of the polarizing plates 1403 and 1404 are different. Alternatively, the wavelength distribution of the extinction coefficient of the polarizing plates 1403 and 1404 may be different.

  FIG. 27 shows an example in which two polarizing plates are stacked on one substrate, but three or more polarizing plates may be stacked.

  Further, due to the characteristics of the phase difference plate, there is a fast axis in the direction orthogonal to the slow axis. Therefore, the arrangement with the polarizing plate can be determined using not only the slow axis but also the fast axis. In this embodiment, since the absorption axis and the slow axis are arranged so as to be shifted by 45 °, in other words, the absorption axis and the fast axis are arranged so as to be shifted by 135 °.

  In this specification, when the shift between the absorption axes and the shift between the absorption axis and the slow axis are described, the above angle is assumed, but if the same effect can be expressed, the shift is slightly deviated from the angle. May be.

  By laminating so that the absorption axes of the laminated polarizing plates are parallel Nicols, it is possible to reduce reflected light from outside light as compared with a single polarizing plate. Therefore, the black display can be darkened, that is, the black luminance can be increased, and the contrast ratio of the display device can be increased.

[Embodiment 21]
In this embodiment mode, a cross-sectional view of a display device of the present invention is shown with reference to FIG.

  Note that in the display device illustrated in FIG. 29, the same components as those in FIG. 26 are denoted by the same reference numerals, and the description of FIG.

  A thin film transistor is formed over a substrate having an insulating surface (hereinafter also referred to as an insulating substrate) 1201 with an insulating layer interposed therebetween. A thin film transistor (also referred to as a TFT) is a semiconductor layer processed into a predetermined shape, a gate insulating layer covering the semiconductor layer, a gate electrode provided on the semiconductor layer through the gate insulating layer, A source electrode or a drain electrode connected to the impurity layer.

  The material used for the semiconductor layer is a semiconductor material containing silicon, and the crystalline state may be any of an amorphous state, a microcrystalline state, and a crystalline state.

  For the insulating layer typified by the gate insulating film, an inorganic material is preferably used, and silicon nitride or silicon oxide can be used. The gate electrode, the source electrode, or the drain electrode may be formed using a conductive material, and includes tungsten, tantalum, aluminum, titanium, silver, gold, molybdenum, copper, and the like.

  The display device can be broadly divided into a pixel portion 1215 and a driver circuit portion 1218. A thin film transistor 1203 provided in the pixel portion 1215 is a switching element of a light-emitting element, and a thin film transistor 1204 provided in the driver circuit portion 1218 is a CMOS circuit. Used. In order to be used as a CMOS circuit, it is composed of a P-channel TFT and an N-channel TFT. A thin film transistor 1203 in the pixel portion 1215 can be controlled by a CMOS circuit provided in the driver circuit portion 1218.

  In FIG. 29, the thin film transistors 1203 and 1204 are top-gate TFTs, but bottom-gate TFTs may be used.

  An insulating layer 1205 having a stacked structure or a single layer structure is formed so as to cover the thin film transistors of the pixel portion 1215 and the driver circuit portion 1218. The insulating layer 1205 can be formed of an inorganic material or an organic material. As the inorganic material, silicon nitride or silicon oxide can be used. As the organic material, polyimide, acrylic, polyamide, polyimide amide, resist, benzocyclobutene, siloxane, or polysilazane can be used.

  Siloxane has a skeletal structure composed of a bond of silicon (Si) and oxygen (O), and an organic group containing at least hydrogen (such as an alkyl group or aromatic hydrocarbon) is used as a substituent. 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. Polysilazane is formed using a liquid material containing a polymer material having a bond of silicon (Si) and nitrogen (N) as a starting material.

  When the insulating layer 1205 is formed using an inorganic material, a surface state along the lower unevenness is obtained, and when the insulating layer 1205 is formed using an organic material, the surface is planarized. For example, in the case where flatness is required for the insulating layer 1205, an organic material may be used. In addition, even if it is an inorganic material, flatness can be provided by thickening.

  The source electrode or the drain electrode is manufactured by forming a conductive layer in an opening provided in the insulating layer 1205 or the like. At this time, a conductive layer functioning as a wiring over the insulating layer 1205 can be formed. The capacitor 1214 can be formed using the conductive layer of the gate electrode, the insulating layer 1205, and the conductive layer of the source or drain electrode.

  Then, a first electrode 1241 connected to either the source electrode or the drain electrode is formed. The first electrode 1241 is formed using a reflective conductive film. As such a conductive film having reflectivity, a conductive film having a high work function such as platinum (Pt) or gold (Au) is used. In addition, since these metals are expensive, they may be stacked on a suitable conductive film such as an aluminum film or a tungsten film to form a pixel electrode in which platinum or gold is exposed at least on the outermost surface.

  An insulating layer 1210 is formed so as to cover an end portion of the first electrode 1241. The insulating layer 1210 can be formed in a manner similar to that of the insulating layer 1205. In order to cover the end portion of the first electrode 1206, an opening is provided in the insulating layer 1210. The end face of the opening may have a taper shape, and a layer formed thereafter can be prevented from being disconnected. For example, when a non-photosensitive resin or a photosensitive resin is used for the insulating layer 1210, the side surface of the opening can be tapered depending on the exposure conditions.

  After that, an electroluminescent layer 1207 is formed in the opening of the insulating layer 1210. The electroluminescent layer 1207 has a layer having each function, specifically, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer. Moreover, the boundary of each layer is not necessarily clear, and some of them may be mixed.

As a specific example of the material for forming the light emitting layer, when red light emission is desired, 4-dicyanomethylene-2-isopropyl-6- [2- (1,1,7,7-tetra Methyljulolidin-9-yl) ethenyl] -4H-pyran (abbreviation: DCJTI), 4-dicyanomethylene-2-methyl-6- [2- (1,1,7,7-tetramethyljulolidine-9- Yl) ethenyl] -4H-pyran (abbreviation: DCJT), 4-dicyanomethylene-2-tert-butyl-6- [2- (1,1,7,7-tetramethyljulolidin-9-yl) ethenyl] -4H-pyran (abbreviation: DCJTB), periflanthene, 2,5-dicyano-1,4-bis [2- (10-methoxy-1,1,7,7-tetramethyljulolidin-9-yl) ethenyl] Benze , Bis [2,3-bis (4-fluorophenyl) Kinokisarinaito] iridium (acetylacetonate) (abbreviation: Ir [Fdpq] 2 acac), or the like can be used. However, the present invention is not limited to these materials, and a substance exhibiting light emission having an emission spectrum peak from 600 nm to 700 nm can be used.

When green light emission is desired, N, N′-dimethylquinacridone (abbreviation: DMQd), coumarin 6, coumarin 545T, tris (8-quinolinolato) aluminum (abbreviation: Alq 3 ), or the like is used for the light emitting layer. Can do. However, the present invention is not limited to these materials, and a substance exhibiting light emission having an emission spectrum peak from 500 nm to 600 nm can be used.

  In order to obtain blue light emission, 9,10-bis (2-naphthyl) -tert-butylanthracene (abbreviation: t-BuDNA), 9,9′-bianthryl, 9,10-diphenyl is used in the light-emitting layer. Anthracene (abbreviation: DPA), 9,10-bis (2-naphthyl) anthracene (abbreviation: DNA), bis (2-methyl-8-quinolinolato) -4-phenylphenolato-gallium (abbreviation: BGaq), bis ( 2-methyl-8-quinolinolato) -4-phenylphenolato-aluminum (abbreviation: BAlq) or the like can be used. However, the present invention is not limited to these materials, and a substance exhibiting light emission having an emission spectrum peak from 400 nm to 500 nm can be used.

When white light emission is desired, TPD (aromatic diamine), 3- (4-tert-butylphenyl) -4-phenyl-5- (4-biphenylyl) -1,2,4-triazole (abbreviation) : TAZ), tris (8-quinolinolato) aluminum (abbreviation: Alq 3), can be used a configuration in which laminated by the Alq 3, Alq 3 doped with Nile red which is a red light emitting pigment deposition method.

After that, the second electrode 1242 is formed. The second electrode 1242 is formed by stacking a light-transmitting conductive film on a thin conductive film with a small work function (preferably 10 to 50 nm) and a small work function. A conductive film having a small work function is a material containing an element belonging to Group 1 or Group 2 of the periodic table (for example, Al, Mg, Ag, Li, Ca, or alloys thereof MgAg, MgAgAl, MgIn, LiAl, LiFAl, CaF). 2 or Ca 3 N 2 ). As the light-transmitting conductive film, indium tin oxide (Indium Tin Oxide (ITO)), zinc oxide (ZnO), indium zinc oxide, zinc oxide added with gallium (GZO), or the like can be given.

Alkali metals such as Li and Cs, alkaline earth metals such as Mg, Ca, and Sr, alloys containing these (Mg: Ag, Al: Li, Mg: In, etc.), and compounds thereof (CaF 2 , nitriding) In addition to calcium), even non-transparent materials such as rare earth metals such as Yb and Er can have translucency by having a very thin film thickness. The second electrode 1242 may be used.

  As described above, the light-emitting element 1209 including the first electrode 1241 and the second electrode 1242, which are a pair of electrodes, and the electroluminescent layer 1207 provided between the electrodes can be formed.

  At this time, since the second electrode 1242 has a light-transmitting property, light can be emitted upward from the electroluminescent layer 1207.

  After that, the insulating substrate 1201 and the counter substrate 1220 are attached to each other with a sealing material 1228. In this embodiment mode, the sealing material 1228 is provided over part of the driver circuit portion 1218; thus, the frame can be narrowed. Needless to say, the arrangement of the sealing material 1228 is not limited to this, and the sealing material 1228 may be provided outside the driver circuit portion 1218.

  The space formed by the bonding is filled with an inert gas such as nitrogen, or is filled with a resin material having a light-transmitting property and a high hygroscopic property. As a result, intrusion of moisture or oxygen that is a cause of deterioration of the light-emitting element 1209 can be prevented. In order to maintain a distance between the insulating substrate 1201 and the counter substrate 1220, a spacer may be provided or the spacer may be hygroscopic. The spacer has a spherical or columnar shape.

  The counter substrate 1220 can be provided with a color filter or a black matrix. The color filter enables full color display even when a monochromatic light emitting layer, for example, a white light emitting layer is used. Even when each of the RGB light emitting layers is used, by providing a color filter, the wavelength of emitted light can be controlled and a beautiful display can be provided. Further, the black matrix can reduce reflection of external light due to wiring or the like.

  After that, a retardation plate 1225, a first polarizing plate 1226, and a second polarizing plate 1227 are provided outside the counter substrate 1220 from which light from the light emitting element is emitted. That is, a circularly polarizing plate having stacked polarizing plates is provided outside the counter substrate 1220.

  At this time, the polarizing plates 1226 and 1227 are also bonded so as to be in a parallel Nicol state.

  As a result, black can be darkened by preventing light leakage from outside light, that is, the black luminance can be increased, and the contrast ratio can be increased.

  Further, by providing the phase difference plate 1225, reflected light from the external light to the display device can be suppressed.

  The retardation plate 1225 may be provided in the same manner as the retardation plate 1421 described in Embodiment 20, and the first polarizing plate 1226 and the second polarizing plate 1227 are also provided in the same manner as the polarizing plates 1403 and 1404. Just do it. In this embodiment, only two polarizing plates are provided, but three or more polarizing plates may be provided.

  In this embodiment mode, a structure in which the polarizing plates illustrated in FIG. 2A are stacked is used as the polarizer. Needless to say, the stacked polarizers illustrated in FIGS. 2B and 2C may be used. .

  Further, the extinction coefficients of the polarizing plates 1226 and 1227 are different. Alternatively, the wavelength distribution of the extinction coefficient of the polarizing plates 1226 and 1227 may be different.

  In this embodiment mode, the driving circuit portion is also formed over the insulating substrate 1201. However, the driving circuit portion may be an IC circuit formed from a silicon wafer. In that case, a video signal or the like from the IC circuit can be input to the switching TFT 1203 through a connection terminal or the like.

  Note that although an active display device is described in this embodiment mode, a circularly polarizing plate including stacked polarizing plates can be provided even in a passive display device. As a result, the contrast ratio can be increased.

  This embodiment mode can be freely combined with the above embodiment mode as necessary.

[Embodiment 22]
In this embodiment mode, the concept of the display device of the present invention will be described. In this embodiment mode, description is made using an electroluminescence element as a light-emitting element.

  30A and 30B illustrate a display device in which light from a light-emitting element is emitted below a substrate. As shown in FIGS. 30A and 30B, a layer 1500 including an electroluminescent element as a light-emitting element is sandwiched between a first substrate 1501 and a second substrate 1502 which are arranged to face each other. Has been. Light emitted from the electroluminescent element can be emitted from the first substrate 1501 (in the direction of the dotted arrow).

  A light-transmitting substrate is used as the first substrate 1501, and a material similar to that of the substrate 1401 in Embodiment 20 may be used for such a light-transmitting substrate.

  The second substrate 1502 may be a light-transmitting substrate, but light from the layer 1500 including an electroluminescent element is not emitted. As described later, an electrode formed on the layer 1500 having an electroluminescent element is formed using a reflective conductive film, or a reflective material is formed over the entire surface of the second substrate 1502. Accordingly, light from the layer 1500 including an electroluminescent element may be reflected to the first substrate 1501 side.

  A phase difference plate (also referred to as a wavelength plate) and a stacked polarizer are provided outside the surface of the first substrate 1501 where light is emitted.

  In this embodiment mode, a structure in which the polarizing plates illustrated in FIG. 2A are stacked is used as the polarizer. Needless to say, the stacked polarizers illustrated in FIGS. 2B and 2C may be used. .

  In this manner, the retardation plate, (λ / 4 plate in the present embodiment) and the stacked polarizing plates are also referred to as a circularly polarizing plate having a stacked polarizing plate (linear polarizing plate). In this embodiment, only two polarizing plates are provided, but three or more polarizing plates may be provided.

  The absorption axis 1551 of the first polarizing plate 1503 and the absorption axis 1552 of the second polarizing plate 1504 are arranged in parallel. That is, the first polarizing plate 1503 and the second polarizing plate 1504, that is, the stacked polarizing plates are arranged in parallel Nicols. In addition, the slow axis 1553 of the retardation film 1521 is arranged to be shifted by 45 ° from the absorption axis 1551 of the first polarizing plate 1503 and the absorption axis 1552 of the second polarizing plate 1504.

  In this specification, when the shift between the absorption axes and the shift between the absorption axis and the slow axis are described, the above angle is assumed, but if the same effect can be expressed, the shift is slightly deviated from the angle. May be.

  These polarizing plates 1503 and 1504 may be formed using the same material as the polarizing plates 1403 and 1404 of Embodiment 20.

  Further, the extinction coefficients of the polarizing plates 1503 and 1504 are different. Alternatively, the wavelength distribution of the extinction coefficient of the polarizing plates 1503 and 1504 may be varied.

  The positional relationship between the absorption axis 1551 of the polarizing plate 1503, the absorption axis 1552 of the polarizing plate 1504, and the slow axis 1553 of the retardation plate 1521 is the same as that in Embodiment 20 (see FIG. 28).

  As for the display device that emits light below the substrate shown in this embodiment, by laminating so that the transmission axes of the laminated polarizing plates are parallel Nicols, compared to a single polarizing plate, Reflected light from outside light can be reduced. Therefore, by making the black display darker, that is, by increasing the black luminance, the contrast ratio of the display device can be increased.

  Note that this embodiment mode can be combined with the above embodiment mode if necessary.

[Embodiment 23]
In this embodiment mode, a cross-sectional view of a display device different from that in Embodiment Mode 21 is shown with reference to FIG.

  29 shows a display device in which light is emitted above a substrate on which a thin film transistor is formed, FIG. 31 shows a display device in which light is emitted below a substrate on which a thin film transistor is formed.

  In FIG. 31, the same components as those in FIG. 29 are denoted by the same reference numerals. The display device in FIG. 31 includes a first electrode 1251, an electroluminescent layer 1207, and a second electrode 1252. The first electrode 1251 may be formed using the same material as the second electrode 1242 in FIG. 29, and the second electrode 1252 may be formed using the same material as the first electrode 1241 in FIG. The electroluminescent layer 1207 may be formed using a material similar to that of the electroluminescent layer 1207 in Embodiment 3. Since the first electrode 1251 has a light-transmitting property, light can be emitted from the electroluminescent layer 1207 downward.

  In addition, a retardation plate 1235, a first polarizing plate 1216, and a second polarizing plate 1217 are provided outside the substrate 1201 from which light from the light-emitting element is emitted. That is, a circularly polarizing plate having stacked polarizing plates is provided outside the substrate 1201. As a result, a display device with a high contrast ratio can be obtained. The retardation plate 1235 may be provided similarly to the retardation plate 1521 described in Embodiment 22, and the first polarizing plate 1216 and the second polarizing plate 1217 are provided in the same manner as the polarizing plates 1503 and 1504. Just do it. In this embodiment, only two polarizing plates are provided, but three or more polarizing plates may be provided.

  Further, the extinction coefficients of the polarizing plates 1216 and 1217 are different. Alternatively, the wavelength distribution of the extinction coefficient of the polarizing plates 1216 and 1217 may be different.

  This embodiment mode can be freely combined with the above embodiment mode, if necessary.

[Embodiment 24]
In this embodiment mode, a structure of a display device including the pixel portion and the driver circuit in Embodiment Modes 16 to 23 will be described.

  FIG. 32 is a block diagram in a state where the scanning line driver circuit portion 1218b and the signal line driver circuit portion 1218a, which are the driver circuit portion 1218, are provided around the pixel portion 1215.

  The pixel portion 1215 includes a plurality of pixels, and a light emitting element and a switching element are provided in the pixel.

  The scan line driver circuit portion 1218b includes a shift register 1351, a level shifter 1354, and a buffer 1355. A signal is generated based on the start pulse (GSP) and the clock pulse (GCK) input to the shift register 1351 and input to the buffer 1355 via the level shifter 1354. In the buffer 1355, the signal is amplified, and the amplified signal is input to the pixel portion 1215 through the scanning line 1371. The pixel portion 1215 is provided with a light-emitting element and a switching element for selecting the light-emitting element, and a signal from the buffer 1355 is input to a gate line included in the switching element. Then, a switching element of a predetermined pixel is selected.

  The signal line driver circuit portion 1218a includes a shift register 1361, a first latch circuit 1362, a second latch circuit 1363, a level shifter 1364, and a buffer 1365. A start pulse (SSP) and a clock pulse (SCK) are input to the shift register 1361, a data signal (DATA) is input to the first latch circuit 1362, and a latch pulse (LAT) is input to the second latch circuit 1363. ) Is entered. DATA is input to the second latch circuit 1363 based on SSP and SCK. The second latch circuit 1363 holds DATA for one row and inputs it to the pixel portion 1215 all at once through the signal line 1372.

  The signal line driver circuit portion 1218a, the scan line driver circuit portion 1218b, and the pixel portion 1215 can be formed using semiconductor elements provided over the same substrate. For example, the thin film transistor can be formed using the thin film transistor provided over the insulating substrate described in the above embodiment mode.

  An equivalent circuit diagram of a pixel included in the display device of this embodiment is described with reference to FIGS.

  FIG. 37A shows an example of an equivalent circuit diagram of a pixel. A signal line 1384, a power supply line 1385, a scanning line 1386, a light-emitting element 1383, transistors 1380 and 1381, and a capacitor 1382 in an intersection region thereof. Have A video signal (also referred to as a video signal) is input to the signal line 1384 by a signal line driver circuit. The transistor 1380 can control supply of the potential of the video signal to the gate of the transistor 1381 in accordance with the selection signal input to the scan line 1386. The transistor 1381 can control supply of current to the light-emitting element 1383 in accordance with the potential of the video signal. The capacitor 1382 can hold a voltage between the gate and the source of the transistor 1381 (referred to as a gate-source voltage). Note that although the capacitor 1382 is illustrated in FIG. 37A, it may not be provided in the case where the gate capacitance of the transistor 1381 or other parasitic capacitance can be used.

  FIG. 37B is an equivalent circuit diagram of a pixel in which a transistor 1388 and a scan line 1389 are newly provided in the pixel shown in FIG. The transistor 1388 can have the same potential as the gate and the source of the transistor 1381 so that no current flows through the light-emitting element 1383, so that a subframe can be generated as compared with a period in which a video signal is input to all pixels. The length of the period can be shortened.

  FIG. 37C is an equivalent circuit diagram of a pixel in which a transistor 1395 and a wiring 1396 are newly provided in the pixel illustrated in FIG. The potential of the gate of the transistor 1395 is fixed by the wiring 1396. The transistor 1381 and the transistor 1395 are connected in series between the power supply line 1385 and the light-emitting element 1383. Thus, in FIG. 37C, the value of the current supplied to the light-emitting element 1383 is controlled by the transistor 1395, and the presence or absence of the current supplied to the light-emitting element 1383 can be controlled by the transistor 1381.

  Note that the pixel circuit included in the display device of the present invention is not limited to the structure shown in this embodiment mode. For example, the pixel circuit having a current mirror may be configured to perform analog gradation display.

  Note that this embodiment mode can be freely combined with the above embodiment mode, if necessary.

[Embodiment 25]
In this embodiment mode, a concept of a display device in which absorption axes of stacked polarizers have a parallel Nicol state, that is, opposite polarizers have a parallel Nicol state will be described.

  This embodiment can be applied to a dual emission light emitting display device (Embodiments 18 to 19).

  As illustrated in FIG. 33, a layer 1460 including a display element is sandwiched between a first substrate 1461 and a second substrate 1462. The display element may be an electroluminescence element.

  Light-transmitting substrates are used as the first substrate 1461 and the second substrate 1462. As the light-transmitting substrate, a material similar to that of the substrate 101 in Embodiment 1 may be used.

  Stacked polarizers are provided on the outer sides of the substrates 1461 and 1462, that is, on the side not in contact with the layer 1460 including the display element. Note that in this embodiment, as the stacked polarizers, a structure in which a polarizing plate having one polarizing film illustrated in FIG. 2A is stacked is used. Of course, it goes without saying that the configuration shown in FIG. 2B or 2C may be used.

  In the light-emitting display device, light from the electroluminescence element is emitted to the first substrate 1461 side and the second substrate 1462 side.

  A first retardation plate 1473, a first polarizing plate 1471, and a second polarizing plate 1472 are sequentially provided on the outer side of the first substrate 1461. The absorption axis 1495 of the first polarizing plate 1471 and the absorption axis 1496 of the second polarizing plate 1472 are parallel, that is, the stacked polarizing plates 1475 are arranged in parallel Nicols. Further, the slow axis 1491 of the first retardation plate 1473 is arranged to be shifted by 45 ° from the absorption axis 1495 of the first polarizing plate 1471 and the absorption axis 1496 of the second polarizing plate 1472.

  FIG. 34A shows a deviation angle between the absorption axis 1495 (and 1496) and the slow axis 1491. The slow axis 1491 makes 45 °, the absorption axis 1495 (and 1496) makes 0 °, and these are shifted by 45 °.

  In addition, a retardation plate 1483, a third polarizing plate 1481, and a fourth polarizing plate 1482 are provided in this order on the outside of the second substrate 1462. The absorption axis 1497 of the third polarizing plate 1481 and the absorption axis 1498 of the fourth polarizing plate 1482 are parallel, that is, the stacked polarizing plates 1485 are arranged in parallel Nicols. Further, the slow axis 1492 of the retardation film 1483 is arranged to be shifted by 45 ° from the absorption axis 1497 of the third polarizing plate 1481 and the absorption axis 1498 of the fourth polarizing plate 1482.

  FIG. 34B shows a deviation angle between the absorption axis 1497 (and 1498) and the slow axis 1492. The slow axis 1492 makes 45 °, the absorption axis 1497 (and 1498) makes 0 °, and they are shifted by 45 °.

  That is, the slow axis 1491 of the first retardation plate 1473 is arranged to be shifted by 45 ° with respect to the absorption axes of the first and second linearly polarizing plates 1471 and 1472, and the third and fourth linearly polarizing plates 1481 are disposed. , And 1482 are arranged so that the slow axis 1492 of the second phase difference plate 1483 is shifted by 45 ° with respect to the absorption axes 1497 and 1498 of the first and second linear polarizers 1471 and 1472. On the other hand, the absorption axes 1497 and 1498 of the third and fourth linearly polarizing plates 1481 and 1482 are arranged in parallel.

  Then, the absorption axis 1495 (and 1496) of the stacked polarizing plate 1475 provided on the first substrate 1461 and the absorption axis 1497 of the stacked polarizing plate 1485 provided on the second substrate 1462 are provided. 1498) are parallel to each other. That is, the stacked polarizing plates 1475 and the stacked polarizing plates 1485, that is, the opposing polarizing plates are arranged in parallel Nicols.

  FIG. 34C shows a state in which the absorption axis 1495 and the slow axis 1491 are overlapped with the absorption axis 1497 and the slow axis 1492, and it can be seen that parallel Nicols are achieved.

  In this specification, when the parallel Nicols and the shift between the absorption axis and the slow axis are described, the above angle is assumed. However, as long as the same effect can be exhibited, the shift may be slightly deviated from the angle. .

  The extinction coefficients of the polarizing plate 1471 and the polarizing plate 1472 are different, and the extinction coefficients of the polarizing plate 1481 and the polarizing plate 1482 are different. Alternatively, the wavelength distributions of the extinction coefficients of the polarizing plates 1471 and 1472 may be different, or the wavelength distributions of the extinction coefficients of the polarizing plates 1481 and 1482 may be different.

  Note that the circularly polarizing plate includes a circularly polarizing plate with a wide band that can widen the wavelength range of 90 ° by overlapping several retardation plates. In this case, the first substrate 1461 is also used. The slow axes of the retardation plates arranged outside the second retardation plate and the retardation plates arranged outside the second substrate 1462 are arranged in parallel with each other, and the absorption of the opposing polarizing plate The shafts may be arranged in parallel Nicols.

  By laminating so that the absorption axes of the laminated polarizing plates are parallel Nicols, light leakage in the absorption axis direction can be reduced. And the polarizing plates which oppose are arrange | positioned so that it may become parallel Nicols. By providing such a circularly polarizing plate, light leakage can be reduced as compared with a circularly polarizing plate arranged so that the polarizing plate single layers are parallel Nicols. For this reason, the contrast ratio of the display device can be increased.

  Note that this embodiment mode can be freely combined with the above embodiment mode, if necessary.

[Embodiment 26]
In this embodiment, a display device having a structure in which the number of polarizers is changed above and below a layer including a display element will be described.

  This embodiment can be applied to a transmissive liquid crystal display device (Embodiment 4 to Embodiment 6) and a dual emission light-emitting display device (Embodiment 16 to Embodiment 17).

  As shown in FIGS. 35A to 35B, a layer 1600 including a display element is sandwiched between a first substrate 1601 and a second substrate 1602 which are arranged to face each other. 35A is a cross-sectional view of the display device of this embodiment mode, and FIG. 35B is a perspective view of the display device of this embodiment mode.

  The display element may be a liquid crystal element in the case of a liquid crystal display device, and may be an electroluminescence element in the case of a light emitting display device.

  As the first substrate 1601 and the second substrate 1602, a light-transmitting substrate is used. As the light-transmitting substrate, 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 plastics typified by polyethylene-terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), polycarbonate (PC), or flexible synthetic resin such as acrylic is applied. can do.

  A stacked polarizer and a single-layer polarizer are provided on the outside of each of the substrates 1601 and 1602, that is, on the side not in contact with the layer 1600 having a display element. Note that in this embodiment, as the stacked polarizers, a structure in which a polarizing plate having one polarizing film illustrated in FIG. 2A is stacked is used. Of course, it goes without saying that the configuration shown in FIG. 2B or 2C may be used.

  In a liquid crystal display device, light from a backlight (not shown) is extracted outside through a layer having a liquid crystal element, a substrate, and a polarizer. In the light-emitting display device, light from the electroluminescence element is emitted to the first substrate 1601 side and the second substrate 1602 side.

  Light passing through the layer having the liquid crystal element or light emitted from the electroluminescence element is linearly polarized by the polarizing plate. That is, a laminated polarizing plate and a polarizing plate having a single layer structure can be described as a laminated linearly polarizing plate. The laminated polarizing plate refers to a state in which two or more polarizing plates are laminated. A single-layer polarizing plate refers to a state where one polarizing plate is provided.

  In this embodiment mode, a display device in which two polarizing plates are stacked on one side and a single-layer polarizing plate is provided on the other side with respect to the layer 1600 having a display element will be described as an example. It is assumed that the two polarizing plates are stacked in contact with each other as shown in FIG.

  A first polarizing plate 1611 and a second polarizing plate 1612 are sequentially provided on the outer side of the first substrate 1601. The absorption axis 1631 of the first polarizing plate 1611 and the absorption axis 1632 of the second polarizing plate 1612 are arranged in parallel. That is, the first polarizing plate 1611 and the second polarizing plate 1612, that is, the stacked polarizing plates 1613 are arranged in parallel Nicols.

  A third polarizing plate 1621 is provided outside the second substrate 1602.

  The absorption axes 1631 and 1632 of the stacked polarizing plate 1613 provided on the first substrate 1601 and the absorption axis 1633 of the polarizing plate 1621 having a single layer structure provided on the second substrate 1602 are orthogonal to each other. It is characterized by doing. That is, the stacked polarizing plates 1613 and the polarizing plate 1621 having a single layer structure, that is, the opposing polarizing plates are arranged so as to form crossed Nicols.

  These polarizing plates 1611, 1612, and 1621 can be formed from known materials. For example, an adhesive surface from the substrate side, a mixed layer of TAC (triacetyl cellulose), PVA (polyvinyl alcohol) and a dichroic dye, and TAC A configuration in which layers are sequentially stacked can be used. Dichroic pigments include iodine and dichroic organic dyes. Moreover, a polarizing plate may be called a polarizing film from the shape.

  Note that, due to the characteristics of the polarizing plate, there is a transmission axis in a direction orthogonal to the absorption axis. Therefore, even when the transmission axes are parallel to each other, it can be called parallel Nicol.

  Further, the extinction coefficients of the polarizing plate 1611 and the polarizing plate 1612 are different. Alternatively, the wavelength distribution of the extinction coefficient between the polarizing plate 1611 and the polarizing plate 1612 may be different.

  As shown in FIGS. 36A to 36B, a first polarizing plate 1611 is arranged in this order from the substrate side on the first substrate 1601 side. That is, on the first substrate 1601 side, the first polarizing plate 1611 forms a single-layer polarizing plate. On the second substrate 1602 side, a second polarizing plate 1621 and a third polarizing plate 1622 are arranged in this order from the substrate side. That is, on the second substrate 1602 side, a stacked polarizing plate 1623 is formed by the second polarizing plate 1621 and the third polarizing plate 1622. Other configurations are the same as those in FIG.

  The absorption axis 1633 of the second polarizing plate 1621 and the absorption axis 1634 of the third polarizing plate 1622 are arranged in parallel. That is, the second polarizing plate 1621 and the third polarizing plate 1622, that is, the stacked polarizing plates 1623 are arranged in parallel Nicols.

  The absorption axis 1631 of the single-layer polarizing plate 1611 provided on the first substrate 1601 and the absorption axes 1633 and 1634 of the stacked polarizing plate 1623 provided on the second substrate 1602 are orthogonal to each other. It is characterized by doing. That is, the polarizing plate 1623 stacked with the polarizing plate 1611 having a single layer structure, that is, the opposing polarizing plates are arranged so as to form a crossed Nicol.

  The extinction coefficients of the polarizing plate 1621 and the polarizing plate 1622 are different. Alternatively, the wavelength distribution of the extinction coefficient between the polarizing plate 1621 and the polarizing plate 1622 may be different.

  Thus, among the polarizing plates arranged so as to face each other, the polarizing plates provided in one direction or the other direction are used as laminated polarizing plates, and the absorption axes of the opposing polarizing plates are crossed Nicols. Also by arranging in this way, light leakage in the absorption axis direction can be reduced. As a result, the contrast ratio of the display device can be increased.

  Note that in this embodiment, an example in which stacked polarizing plates are used as an example of stacked polarizers, one polarizing plate is provided on one substrate side, and two polarizing plates are provided on the other substrate side is described. However, the number of polarizers to be stacked is not limited to two and may be three or more.

  Note that this embodiment can be implemented freely combining with any of the other embodiments and examples in this specification.

[Embodiment 27]
In this embodiment, a display device using a circularly polarizing plate having stacked polarizers and a circularly polarizing plate having one polarizer above and below a layer having a display element will be described.

  This embodiment can be applied to a transmissive liquid crystal display device (Embodiments 7 to 9) and a dual emission light emitting display device (Embodiments 18 to 19).

  As shown in FIG. 38, a layer 1560 having a display element is sandwiched between a first substrate 1561 and a second substrate 1562 which are arranged to face each other.

  As shown in FIG. 38, a retardation plate 1575, a first polarizing plate 1571, and a second polarizing plate 1572 are arranged in this order from the substrate side on the first substrate 1561 side. In other words, on the first substrate 1561 side, a polarizing plate 1573 which is stacked by the first polarizing plate 1571 and the second polarizing plate 1572 is formed. In addition, on the second substrate 1562 side, a retardation plate 1576 and a third polarizing plate 1581 are arranged in this order from the substrate side. That is, on the second substrate 1562 side, the third polarizing plate 1581 forms a single-layer polarizing plate.

  The display element may be a liquid crystal element in the case of a liquid crystal display device, and may be an electroluminescence element in the case of a light emitting display device.

  A light-transmitting substrate is used as the first substrate 1561 and the second substrate 1562. As the light-transmitting substrate, 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 plastics typified by polyethylene-terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), polycarbonate (PC), or flexible synthetic resin such as acrylic is applied. can do.

  On the outside of each of the substrates 1561 and 1562, that is, on the side not in contact with the layer 1560 having a display element, a polarizer laminated with a retardation plate, and a retardation plate and a single-layer polarizer are provided. Note that in this embodiment, as the stacked polarizers, a structure in which a polarizing plate having one polarizing film illustrated in FIG. 2A is stacked is used. Of course, it goes without saying that the configuration shown in FIG. 2B or 2C may be used.

  In a liquid crystal display device, light from a backlight (not shown) is extracted outside through a layer having a liquid crystal element, a substrate, a retardation plate, and a polarizer. In the light-emitting display device, light from the electroluminescence element is emitted to the first substrate 1561 side and the second substrate 1562 side.

  Light emitted from the electroluminescence element is circularly polarized by the retardation plate and linearly polarized by the polarizing plate. That is, a laminated polarizing plate and a polarizing plate having a single layer structure can be described as a laminated linearly polarizing plate. The laminated polarizing plate refers to a state in which two or more polarizing plates are laminated. A single-layer polarizing plate refers to a state where one polarizing plate is provided.

  In the case of a liquid crystal display device, a retardation plate is provided in order to obtain a wide viewing angle, and which retardation plate is to be used may be appropriately determined depending on the liquid crystal driving mode.

  The absorption axis 1595 of the first polarizing plate 1571 and the absorption axis 1596 of the second polarizing plate 1572 are stacked so as to be parallel. This parallel state is called parallel Nicol.

  The laminated polarizing plates 1573 are arranged so as to be parallel Nicols.

  The absorption axis 1595 (and 1596) of the laminated polarizing plate 1573 and the absorption axis 1597 of the single-layer polarizing plate 1581 are orthogonal to each other. That is, the polarizing plates facing each other are arranged so that the absorption axes are orthogonal. This orthogonal state is called crossed Nicol.

  Note that, due to the characteristics of the polarizing plate, there is a transmission axis in a direction orthogonal to the absorption axis. Therefore, even when the transmission axes are parallel to each other, it can be called parallel Nicol. Moreover, when the transmission axes are orthogonal to each other, it can be called crossed Nicols.

  Further, the extinction coefficients of the polarizing plate 1571 and the polarizing plate 1572 are different. Alternatively, the wavelength distribution of the extinction coefficient between the polarizing plate 1571 and the polarizing plate 1572 may be different.

  38 and 40, the shift of the slow axes 1591 and 1592 of the retardation plate in the light-emitting display device having the electroluminescence element will be described. In FIG. 38, an arrow 1591 represents the slow axis of the phase difference plate 1575, and an arrow 1592 represents the slow axis of the phase difference plate 1576.

  The slow axis 1591 of the retardation film 1575 is arranged to be shifted by 45 ° from the absorption axis 1595 of the first polarizing plate 1571 and the absorption axis 1596 of the second polarizing plate 1572.

  FIG. 40A shows a deviation angle between the absorption axis 1595 of the first polarizing plate 1571 and the slow axis 1591 of the phase difference plate 1575. The slow axis 1591 of the retardation plate 1575 forms 135 °, the absorption axis 1595 of the first polarizing plate 1571 forms 90 °, and these are shifted by 45 °.

  The slow axis 1592 of the phase difference plate 1576 is disposed so as to be shifted by 45 ° from the absorption axis 1597 of the third polarizing plate 1581.

  FIG. 40B shows a deviation angle of the absorption axis 1597 of the third polarizing plate 1581. The slow axis 1592 of the retardation plate 1576 forms 45 °, the absorption axis 1597 of the third polarizing plate 1581 forms 0 °, and these are shifted by 45 °. That is, the slow axis 1591 of the phase difference plate 1575 is arranged to be shifted by 45 ° with respect to the absorption axis 1595 of the first linearly polarizing plate 1571 and the absorption axis 1596 of the second linearly polarizing plate 1572, and the third linearly polarized light The slow axis 1592 of the phase difference plate 1576 is arranged to be shifted by 45 ° with respect to the absorption axis 1597 of the plate 1581.

  An absorption axis 1595 (and 1596) of the stacked polarizing plate 1573 provided on the first substrate 1561 and an absorption axis 1597 of the polarizing plate 1581 having a single layer structure provided on the second substrate 1562 Are orthogonal to each other. That is, the opposing polarizing plates are arranged so as to form a crossed Nicols.

  In FIG. 40C, the absorption axis 1595 and the slow axis 1591 are indicated by solid lines, the absorption axis 1597 and the slow axis 1592 are indicated by dotted lines, and a state in which these are overlapped is shown. FIG. 40C shows that the absorption axis 1595 and the absorption axis 1597 have a crossed Nicols state, and the slow axis 1591 and the slow axis 1592 have a crossed Nicols state.

  Further, due to the characteristics of the phase difference plate, there is a fast axis in a direction orthogonal to the slow axis. Therefore, the arrangement with the polarizing plate can be determined using not only the slow axis but also the fast axis. In this embodiment, since the absorption axis and the slow axis are arranged so as to be shifted by 45 °, in other words, the absorption axis and the fast axis are arranged so as to be shifted by 135 °.

  In this specification, when the shift between the absorption axes and the shift between the absorption axis and the slow axis are described, the above angle is assumed, but if the same effect can be expressed, the shift is slightly deviated from the angle. May be.

  FIG. 39 shows a stacked structure different from that in FIG. In FIG. 39, a retardation film 1575 and a first polarizing plate 1571 are arranged in this order from the substrate side on the first substrate 1561 side. That is, on the first substrate 1561 side, the first polarizing plate 1571 forms a single-layer polarizing plate. Further, on the second substrate 1562 side, a retardation plate 1576, a stacked second polarizing plate 1581, and a third polarizing plate 1582 are arranged in this order from the substrate side. That is, on the second substrate 1562 side, a stacked polarizing plate 1583 is formed by the second polarizing plate 1581 and the third polarizing plate 1582.

  The absorption axis 1598 of the third polarizing plate 1582 is parallel to the absorption axis 1597 of the second polarizing plate 1581. Therefore, the deviation between the absorption axis and the slow axis is the same as that of the configuration of FIG.

  Further, the extinction coefficients of the polarizing plate 1581 and the polarizing plate 1582 are different. Alternatively, the wavelength distribution of the extinction coefficient between the polarizing plate 1581 and the polarizing plate 1582 may be different.

  By having a polarizing plate laminated on one circular polarizing plate in this way and arranging it so that the absorption axes of opposing polarizing plates are crossed Nicols, light leakage in the absorption axis direction can be reduced. it can. As a result, the contrast ratio of the display device can be increased.

  Note that in this embodiment, an example in which stacked polarizing plates are used as an example of stacked polarizers, one polarizing plate is provided on one substrate side, and two polarizing plates are provided on the other substrate side is described. However, the number of polarizers to be stacked is not limited to two and may be three or more.

  Note that this embodiment can be implemented freely combining with any of the other embodiments and examples in this specification.

[Embodiment 28]
In this embodiment, a concept of a display device using a circularly polarizing plate having stacked polarizers and a circularly polarizing plate having one polarizer will be described.

  This embodiment can be applied to a dual emission light-emitting display device (Embodiment 25).

  As shown in FIG. 41, a layer 1660 including a display element is sandwiched between a first substrate 1661 and a second substrate 1662 which are arranged to face each other.

  The display element may be an electroluminescence element.

  A light-transmitting substrate is used as the first substrate 1661 and the second substrate 1662. As the light-transmitting substrate, a material similar to that of the substrates 1561 and 1562 described in Embodiment 27 may be used.

  A stacked polarizer and a single-layer polarizer are provided on the outside of each of the substrates 1661 and 1662, that is, on the side not in contact with the layer 1660 having a display element. Note that in this embodiment, as the stacked polarizers, a structure in which a polarizing plate having one polarizing film illustrated in FIG. 2A is stacked is used. Of course, it goes without saying that the configuration shown in FIG. 2B or 2C may be used.

  In the light-emitting display device, light from the electroluminescence element emits light to the first substrate 1661 side and the second substrate 1662 side.

  Light emitted from the electroluminescence element is linearly polarized by the polarizing plate. That is, a laminated polarizing plate and a polarizing plate having a single layer structure can be described as a laminated linearly polarizing plate. The laminated polarizing plate refers to a state in which two or more polarizing plates are laminated. A single-layer polarizing plate refers to a state where one polarizing plate is provided.

  As shown in FIG. 41, a retardation plate 1675, a first polarizing plate 1671, and a second polarizing plate 1672 are arranged in this order from the substrate side on the first substrate 1661 side. In other words, on the first substrate 1661 side, a polarizing plate 1673 stacked by the first polarizing plate 1671 and the second polarizing plate 1672 is formed. In addition, a retardation film 1676 and a third polarizing plate 1681 are arranged on the second substrate 1662 side in this order from the substrate side. That is, on the second substrate 1662 side, the third polarizing plate 1681 forms a single-layer polarizing plate.

  The absorption axis 1695 of the first polarizing plate 1671 and the absorption axis 1696 of the second polarizing plate 1672 are parallel, that is, the stacked polarizing plates 1673 are arranged in parallel Nicols. Further, the slow axis 1691 of the first retardation plate 1675 is arranged to be shifted by 45 ° from the absorption axis 1695 of the first polarizing plate 1671 and the absorption axis 1696 of the second polarizing plate 1672.

  FIG. 43A shows the deviation angle of the absorption axis 1695 (and 1696) and the slow axis 1691. FIG. The slow axis 1691 makes 45 °, the absorption axis 1695 (and 1696) makes 0 °, and they are shifted by 45 °.

  In addition, a retardation film 1676 and a third polarizing plate 1681 are sequentially provided on the outer side of the second substrate 1662. The slow axis 1692 of the retardation film 1676 is disposed so as to be shifted by 45 ° from the absorption axis 1697 of the third polarizing plate 1681.

  FIG. 43B shows a deviation angle between the absorption axis 1697 and the slow axis 1692. The slow axis 1692 forms 45 °, the absorption axis 1697 forms 0 °, and these are shifted by 45 °.

  That is, the slow axis 1691 of the phase difference plate 1675 is arranged to be shifted by 45 ° with respect to the absorption axes 1695 and 1696 of the first and second linearly polarizing plates 1671 and 1672, and the absorption axis of the third linearly polarizing plate 1681 is obtained. 1697 is arranged such that the slow axis 1692 of the phase difference plate 1676 is shifted by 45 °, and the third linear polarizing plate 1681 with respect to the absorption axes 1695 and 1696 of the first and second linear polarizing plates 1671 and 1672. These absorption axes 1697 are arranged in parallel.

  The absorption axis 1695 (and 1696) of the stacked polarizing plate 1673 provided on the first substrate 1661 and the absorption axis 1697 of the product polarizing plate 1681 provided on the second substrate 1662 are parallel to each other. It is characterized by doing. In other words, the stacked polarizing plates 1673 and the polarizing plate 1681 having a single layer structure, that is, the opposing polarizing plates are arranged in parallel Nicols.

  FIG. 43C shows a state in which the absorption axis 1695 and the slow axis 1691 are overlapped with the absorption axis 1697 and the slow axis 1692, which indicates that parallel Nicols are achieved.

  In this specification, when the parallel Nicols and the shift between the absorption axis and the slow axis are described, the above angle is assumed. However, as long as the same effect can be exhibited, the shift may be slightly deviated from the angle. .

  Further, the extinction coefficients of the polarizing plate 1671 and the polarizing plate 1672 are different. Alternatively, the wavelength distribution of the extinction coefficient between the polarizing plate 1671 and the polarizing plate 1672 may be different.

  Note that the circularly polarizing plate includes a circularly polarizing plate with a wide band that can widen a wavelength range of 90 degrees of phase difference by overlapping several retardation plates. In this case, the first substrate 1661 is also used. The slow axes of the retardation plates arranged outside the second retardation plate and the retardation plates arranged outside the second substrate 1662 are arranged in parallel with each other, and the absorption of the opposing polarizing plate The shafts may be arranged in parallel Nicols.

  By laminating so that the absorption axes of the laminated polarizing plates are parallel Nicols, light leakage in the absorption axis direction can be reduced. And the polarizing plates which oppose are arrange | positioned so that it may become parallel Nicols. By providing such a circularly polarizing plate, light leakage can be reduced as compared with a circularly polarizing plate arranged so that the polarizing plate single layers are parallel Nicols. For this reason, the contrast ratio of the display device can be increased.

  Further, as shown in FIG. 42, a retardation plate 1675 and a first polarizing plate 1671 are arranged in this order from the substrate side on the first substrate 1661 side. That is, on the first substrate 1661 side, the first polarizing plate 1671 forms a single-layer polarizing plate. In addition, a retardation plate 1676, a second polarizing plate 1681, and a third polarizing plate 1682 are arranged in this order from the substrate side on the second substrate 1662 side. That is, on the second substrate 1662 side, a stacked polarizing plate 1683 is configured by the second polarizing plate 1681 and the third polarizing plate 1682.

  The absorption axis 1698 of the third polarizing plate 1682 is parallel to the absorption axis 1697 of the second polarizing plate 1681. Therefore, the deviation between the absorption axis and the slow axis is the same as that of the configuration of FIG.

  Further, the extinction coefficients of the polarizing plate 1681 and the polarizing plate 1682 are different. Alternatively, the wavelength distribution of the extinction coefficient between the polarizing plate 1681 and the polarizing plate 1682 may be different.

In this way, it is possible to reduce light leakage in the direction of the transmission axis by having a polarizing plate laminated on one circular polarizing plate and arranging the transmission axes of the opposing polarizing plates to be parallel Nicols. it can. As a result, the contrast ratio of the display device can be increased.

  Note that in this embodiment, an example in which stacked polarizing plates are used as an example of stacked polarizers, one polarizing plate is provided on one substrate side, and two polarizing plates are provided on the other substrate side is described. However, the number of polarizers to be stacked is not limited to two and may be three or more.

  Note that this embodiment can be implemented freely combining with any of the other embodiments and examples in this specification.

[Embodiment 29]

  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. The configuration in which a plurality of polarizing plates of the present invention is provided can be applied to either a vertical electric field method or a horizontal electric field method. Therefore, in this embodiment mode, a mode in which the liquid crystal display device of the present invention is applied to various liquid crystal modes will be described.

  This embodiment can be applied to liquid crystal display devices (Embodiments 4 to 15, Embodiments 26 to 27).

  In the present embodiment, the same components are denoted by the same reference numerals.

  First, FIGS. 44A to 44B are schematic views of a liquid crystal display device in a TN (Twisted Nematic) mode.

  A layer 120 having a liquid crystal element is sandwiched between a first substrate 121 and a second substrate 122 which are arranged to face each other. A layer 125 having a polarizer is formed on the first substrate 121 side, and a layer 126 having a polarizer is formed on the second substrate 122 side. The layers 125 and 126 having a polarizer may be configured based on the fourth to fifteenth embodiments and the twenty-sixth to twenty-seventh embodiments. That is, a circularly polarizing plate including stacked polarizers may be provided, or a configuration in which a retardation plate is not provided using only stacked polarizers may be used. In addition, the number of polarizers provided above and below the layer having the display element may be the same or different. Furthermore, the absorption axis of the laminated polarizers is crossed Nicols above and below the substrate. In the case of manufacturing a reflective liquid crystal display device, one of the layers 125 and 126 having a polarizer is not necessarily formed. However, in the case of a reflective liquid crystal display device, a structure is provided in which both a retardation plate and a polarizer are provided in order to perform black display.

  In the present embodiment, the extinction coefficients of the polarizers stacked on one substrate are different. Or you may vary the wavelength distribution of the extinction coefficient of each polarizer laminated on one substrate.

  A first electrode 127 and a second electrode 128 are provided over the first substrate 121 and the second substrate 122, respectively. In the case of a transmissive liquid crystal display device, at least one substrate is formed so as to have translucency. In the case of a reflective liquid crystal display device, either the first electrode 127 or the second electrode 128 is made reflective, and the other is made translucent.

  In the liquid crystal display device having such a structure, in the normally white mode, when voltage is applied to the first electrode 127 and the second electrode 128 (referred to as a vertical electric field mode), FIG. As shown, black display is performed. At this time, the liquid crystal molecules 116 are aligned vertically. Then, in the case of a transmissive liquid crystal display device, light from the backlight cannot pass through the substrate and is displayed in black. In the case of a reflection type liquid crystal display device, a retardation plate is provided, and light from outside light is transmitted through only a component of light that vibrates in the transmission axis direction of the polarizer and becomes linearly polarized light. When passing through, it becomes circularly polarized light (for example, right circularly polarized light). When the right circularly polarized light is reflected by the reflecting plate (or the reflecting electrode), it becomes left circularly polarized light. ) Is linearly polarized light that vibrates. Accordingly, the light is absorbed by the absorption axis of the polarizer, so that black display is obtained.

  Then, as shown in FIG. 44B, when no voltage is applied between the first electrode 127 and the second electrode 128, white display is performed. At this time, the liquid crystal molecules 116 are aligned horizontally and are rotated in a plane. As a result, in the case of a transmissive liquid crystal display device, light from a backlight can pass through a substrate provided with layers 125 and 126 having polarizers, and a predetermined video display is performed. In the case of a reflective liquid crystal display device, the reflected light passes through a substrate provided with a layer having a polarizer, whereby 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 121 side or the second substrate 122 side.

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

  45A to 45B are schematic views of a liquid crystal display device in a VA (Vertically Aligned) mode. 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.

  The liquid crystal display devices in FIGS. 45A to 45B are similar to those in FIGS. 44A to 44B, and are over the first substrate 121 and the second substrate 122, respectively. A first electrode 127 and a second electrode 128 are provided. In the case of a transmissive liquid crystal display device, at least one of the electrodes is formed so as to have translucency. In the case of a reflective liquid crystal display device, either the first electrode 127 or the second electrode 128 is made reflective, and the other is made translucent.

  In a liquid crystal display device having such a structure, when voltage is applied to the first electrode 127 and the second electrode 128 (vertical electric field method), white display is performed as shown in FIG. It becomes a state. At this time, the liquid crystal molecules 116 are arranged side by side. Then, in the case of a transmissive liquid crystal display device, light from the backlight can pass through the substrate provided with the layers 125 and 126 having polarizers, and a predetermined video display is performed. In the case of a reflective liquid crystal display device, the reflected light passes through a substrate provided with a layer having a polarizer, whereby 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 121 side or the second substrate 122 side.

  Then, as shown in FIG. 45B, when no voltage is applied between the first electrode 127 and the second electrode 128, black display, that is, an off state is obtained. At this time, the liquid crystal molecules 116 are aligned vertically. As a result, in the case of a transmissive liquid crystal display device, light from the backlight cannot pass through the substrate, resulting in black display. In the case of a reflection type liquid crystal display device, a retardation plate is provided, and light from outside light is transmitted through only a component of light that vibrates in the transmission axis direction of the polarizer and becomes linearly polarized light. When passing through, it becomes circularly polarized light (for example, right circularly polarized light). When the right circularly polarized light is reflected by the reflecting plate (or the reflecting electrode), it becomes left circularly polarized light. ) Is linearly polarized light that vibrates. Accordingly, the light is absorbed by the absorption axis of the polarizer, so that black display is obtained.

  In this way, in the off state, the liquid crystal molecules 116 rise perpendicularly to the substrate and display black, and in the on state, the liquid crystal molecules 116 tilt horizontally with respect to the substrate and display white. In the transmissive liquid crystal display device, the light from the polarized backlight passes through the cell without being affected by the liquid crystal molecules 116 in the off state, and the liquid crystal molecules 116 rise in the off state. It can be completely blocked by a polarizer. The case of the reflective liquid crystal display device is as described above. Therefore, further improvement in contrast is expected by providing a layer having a polarizer.

  As the liquid crystal material used for the VA mode, a known material may be used.

  The present invention can also be applied to the MVA mode in which the alignment of the liquid crystal is divided.

  46A to 46B are schematic views of a liquid crystal display device in an MVA (Multi-domain Vertically Aligned) mode.

  The liquid crystal display devices in FIGS. 46A to 46B are similar to those in FIGS. 44A to 44B, and are over the first substrate 121 and the second substrate 122, respectively. A first electrode 127 and a second electrode 128 are provided. In the case of a transmissive liquid crystal display device, the electrode opposite to the backlight, that is, the electrode on the display surface side, for example, the second electrode 128 is formed so as to have at least translucency. In the case of a reflective liquid crystal display device, either the first electrode 127 or the second electrode 128 is made reflective, and the other is made translucent.

  A plurality of protrusions (also referred to as ribs) 118 are formed on the first electrode 127 and the second electrode 128, respectively. The protrusion 118 may be formed of a resin such as acrylic. The protrusion 118 may be bilaterally symmetrical, preferably a tetrahedron.

  In the MVA method, the liquid crystal molecules 116 are driven to be symmetrical with respect to the protrusion 118. This suppresses the difference in color viewed from the left and right. When the direction in which the liquid crystal molecules 116 are tilted within the pixel is changed, color unevenness does not occur from any line of sight.

  FIG. 46A shows a state where an applied voltage is applied, that is, an on state. In the ON state, the liquid crystal molecules 116 are tilted in the tilt direction of the protrusion 118 due to the application of the tilt electric field. As a result, the major axis of the liquid crystal molecules 116 intersects with the absorption axis of the polarizer, so that light passes through one of the polarizer-containing layers 125 and 126 on the output side, resulting in a bright state (white display).

  FIG. 46B shows a state where no applied voltage is applied, that is, an off state. In the off state, the liquid crystal molecules 116 are aligned perpendicular to the substrates 121 and 122. For this reason, incident light entering from one of the layers 125 and 126 having a polarizer provided on the substrate 121 or the substrate 122 passes through the liquid crystal molecules 116 as it is, so that the layers 125 and 126 having a polarizer on the output side and Orthogonal to the other of 126. Therefore, since no light is output, the state is dark (black display).

  By providing the protrusion 118, the liquid crystal molecules 116 are driven so as to tilt in the tilt direction of the protrusion 118, and a display having symmetry and good viewing angle characteristics can be obtained.

  47A to 47B show another example of the MVA mode. In this embodiment mode, the first electrode 127 is provided with a protrusion 118 and the other of the first electrode 127 or the second electrode 128 mode, in this embodiment mode. Then, a part of the second electrode 128 is removed to form the slit 119.

  FIG. 47A shows a state where an applied voltage is applied, that is, an on state. When an applied voltage is applied in the on state, an oblique electric field is generated in the vicinity of the slit 119 even if the protrusion 118 is not provided. The liquid crystal molecules 116 are tilted in the inclination direction of the protrusion 118 due to the application of the gradient electric field. As a result, the major axis of the liquid crystal molecules 116 intersects with the absorption axis of the polarizer, so that light passes through one of the polarizer-containing layers 125 and 126 on the output side, resulting in a bright state (white display).

  FIG. 47B shows a state where the applied voltage is not applied, that is, in the off state. In the off state, the liquid crystal molecules 116 are aligned perpendicular to the substrates 121 and 122. For this reason, incident light entering from one of the layers 125 and 126 having a polarizer provided on the substrate 121 or the substrate 122 passes through the liquid crystal molecules 116 as it is, so that the layers 125 and 126 having a polarizer on the output side and Orthogonal to the other of 126. Therefore, since no light is output, the state is dark (black display).

  Note that a known liquid crystal material may be used for the MVA mode.

  FIG. 48 is an example of a top view of an arbitrary pixel in the MVA mode liquid crystal display device in FIGS. 47A to 47B.

  The TFT 251 serving as a pixel switching element includes a gate wiring 252, a gate insulating film, an island-shaped semiconductor film 253, a source electrode 257, and a drain electrode 256.

  Note that the pixel electrode 259 is electrically connected to the drain electrode 256.

  A plurality of grooves 263 are formed in the pixel electrode 259.

  In the region where the gate wiring 252 and the pixel electrode 259 overlap, an auxiliary capacitor 267 is formed using a gate insulating film as a dielectric.

  A plurality of protrusions (also referred to as ribs) 265 are formed on the counter electrode (not shown) side provided on the counter substrate. The protrusion 265 may be formed of a resin such as acrylic. The protrusion 265 may be bilaterally symmetrical, preferably a tetrahedron.

  53A to 53B are schematic views of a liquid crystal display device in a PVA (Patterned Vertical Alignment) mode.

  53A to 53B are diagrams showing the movement of the liquid crystal molecules 116. FIG.

  In the PVA mode, the groove 173 of the electrode 127 and the groove 174 of the electrode 128 are shifted from each other, and the liquid crystal molecules 116 are oriented toward the grooves 173 and 174 that are shifted from each other, whereby light is transmitted.

  FIG. 53A shows a state where an applied voltage is applied, that is, an on state. In the on state, the liquid crystal molecules 116 are inclined obliquely due to the application of an electric field obliquely. As a result, the major axis of the liquid crystal molecules 116 intersects with the absorption axis of the polarizer, so that light passes through one of the polarizer-containing layers 125 and 126 on the output side, resulting in a bright state (white display).

  FIG. 53B shows a state where the applied voltage is not applied, that is, in the off state. In the off state, since the liquid crystal molecules 116 are aligned perpendicular to the substrates 121 and 122, incident light from the layers 125 and 126 having a polarizer provided on the substrate 121 or the substrate 122 remains as it is. Since the light passes through 116, it is orthogonal to the polarizing plate on the output side. Therefore, since no light is output, the state is dark (black display).

  By providing the electrode 127 with the groove 173 and the electrode 128 with the groove 174, the liquid crystal molecules 116 are driven obliquely by an oblique electric field toward the grooves 173 and 174, and not only in the vertical and horizontal directions but also in the diagonal direction. A display having symmetry and good viewing angle characteristics can be obtained.

  FIG. 54 is an example of a top view of an arbitrary pixel in the PVA mode liquid crystal display device of FIGS. 53 (A) to 53 (B).

  The TFT 191 serving as a pixel switching element includes a gate wiring 192, a gate insulating film, an island-shaped semiconductor film 193, a source electrode 197, and a drain electrode 196.

  Although the source electrode 197 and the source wiring 198 are separated for convenience, they are formed of the same conductive film and connected to each other. The drain electrode 196 is also formed using the same material and the same process as the source electrode 197 and the source wiring 198.

  A plurality of grooves 207 are formed in the pixel electrode 199 electrically connected to the drain electrode 196.

  A storage capacitor 208 is formed in a region where the pixel electrode 199 and the gate wiring 192 overlap with a gate insulating film interposed therebetween.

  A plurality of grooves 206 are formed in a counter electrode (not shown) formed on the counter substrate. The counter electrode grooves 206 are arranged alternately with the grooves 207 of the pixel electrode 199.

  In a PVA liquid crystal display device, a display having symmetry and good viewing angle characteristics can be obtained.

  49A to 49B 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.

  The liquid crystal display devices in FIGS. 49A to 49B are similar to those in FIGS. 44A to 44B, and are over the first substrate 121 and the second substrate 122, respectively. A first electrode 127 and a second electrode 128 are provided. In the case of a transmissive liquid crystal display device, an electrode opposite to the backlight, that is, an electrode on the display surface side, for example, the second electrode 128 is formed so that at least one of the electrodes has translucency. In the case of a reflective liquid crystal display device, either the first electrode 127 or the second electrode 128 is made reflective, and the other is made translucent.

  In the liquid crystal display device having such a structure, when voltage is applied to the first electrode 127 and the second electrode 128 (vertical electric field method), black display is performed as shown in FIG. At this time, the liquid crystal molecules 116 are aligned vertically. As a result, in the case of a transmissive liquid crystal display device, light from the backlight cannot pass through the substrate, resulting in black display. In the case of a reflection type liquid crystal display device, a retardation plate is provided, and light from outside light is transmitted through only a component of light that vibrates in the transmission axis direction of the polarizer and becomes linearly polarized light. When passing through, it becomes circularly polarized light (for example, right circularly polarized light). When the right circularly polarized light is reflected by the reflecting plate (or the reflecting electrode), it becomes left circularly polarized light. ) Is linearly polarized light that vibrates. Accordingly, the light is absorbed by the absorption axis of the polarizer, so that black display is obtained.

  As shown in FIG. 49B, when no voltage is applied between the first electrode 127 and the second electrode 128, white display is performed. At this time, the liquid crystal molecules 116 are arranged obliquely. Then, in the case of a transmissive liquid crystal display device, light from the backlight can pass through the substrate provided with the layers 125 and 126 having polarizers, and a predetermined video display is performed. In the case of a reflective liquid crystal display device, the reflected light passes through a substrate provided with a layer having a polarizer, whereby 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 121 side or the second substrate 122 side.

  In such an OCB mode, a wide viewing angle can be realized by compensating the birefringence in the liquid crystal layer generated in other modes only by the liquid crystal layer, and the contrast ratio is increased by the layer having the polarizer of the present invention. be able to.

  50A to 50B are schematic views of a liquid crystal display device in an IPS (In-Plane Switching) mode. 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 155 and 156 is provided over the second substrate 122. The pair of electrodes 155 and 156 may each have a light-transmitting property.

  In the liquid crystal display device having such a structure, when voltage is applied to the pair of electrodes 155 and 156, an on state in which white display is performed is performed as illustrated in FIG. Then, in the case of a transmissive liquid crystal display device, light from the backlight can pass through the substrate provided with the layers 125 and 126 having polarizers, and a predetermined video display is performed. In the case of a reflective liquid crystal display device, the reflected light passes through a substrate provided with a layer having a polarizer, whereby 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 121 side or the second substrate 122 side.

  Then, as shown in FIG. 50B, when no voltage is applied between the pair of electrodes 155 and 156, black display, that is, an off state is set. At this time, the liquid crystal molecules 116 are arranged side by side and rotated in a plane. As a result, in the case of a transmissive liquid crystal display device, light from the backlight cannot pass through the substrate, resulting in black display. In the case of a reflective liquid crystal display device, a retardation plate is provided as necessary, and black display is achieved by shifting the phase by 90 ° including the liquid crystal layer.

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

  FIGS. 51A to 51D illustrate examples of the pair of electrodes 155 and 156. In FIG. 51A, the pair of electrodes 155 and 156 have a wave shape. In FIG. 51B, the pair of electrodes 155 and 156 have a partially circular shape. In FIG. 51C, a grid-like electrode 155 and a comb-like electrode 156 are formed. In FIG. 51D, each of the pair of electrodes 155 and 156 is a comb-like electrode.

  FIG. 52 is an example of a top view of an arbitrary pixel in the IPS mode liquid crystal display device in FIGS. 50A to 50B.

  A gate wiring 232 and a common wiring 233 are formed on the substrate. The gate wiring 232 and the common wiring 233 are formed using the same material, the same layer, and the same process.

  The TFT 231 serving as a pixel switching element includes a gate wiring 232, a gate insulating film, an island-shaped semiconductor film 237, a source electrode 238, and a drain electrode 236.

  The source electrode 238 and the source wiring 235 are separated for convenience, but are formed of the same conductive film and connected to each other. The drain electrode 236 is also formed using the same material and the same process as the source electrode 238 and the source wiring 235.

  The drain electrode 236 and the pixel electrode 241 are also electrically connected.

  Each of the pixel electrode 241 and the plurality of common electrodes 242 is formed using the same material and the same process. The common electrode 242 is electrically connected to the common wiring 233 through a contact hole 234 in the gate insulating film.

  A horizontal electric field parallel to the substrate is generated between the pixel electrode 241 and the common electrode 242 to control the liquid crystal.

  In the IPS mode liquid crystal display device, since the liquid crystal molecules 116 do not rise obliquely, the optical characteristics change little depending on the viewing angle, and wide viewing characteristics can be obtained.

  When the layer having the polarizer of the present invention is applied to a horizontal electric field 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.

  FIGS. 55A to 55B are schematic diagrams of liquid crystal display devices in FLC (ferroelectric liquid crystal, Ferro-Electric Liquid Crystal) mode and AFLC (Anti-ferroelectric liquid crystal, Antiferro-Electric Liquid Crystal) mode. Show.

  The liquid crystal display devices in FIGS. 55A to 55B are similar to those in FIGS. 44A to 44B, and are respectively provided over the first substrate 121 and the second substrate 122. A first electrode 127 and a second electrode 128 are provided. In the case of a transmissive liquid crystal display device, the electrode opposite to the backlight, that is, the electrode on the display surface side, for example, the second electrode 128 is formed so as to have at least translucency. In the case of a reflective liquid crystal display device, either the first electrode 127 or the second electrode 128 is made reflective, and the other is made translucent.

  In a liquid crystal display device having such a structure, when voltage is applied to the first electrode 127 and the second electrode 128 (referred to as a vertical electric field mode), white display is obtained as shown in FIG. . At this time, the liquid crystal molecules 116 are aligned horizontally and are rotated in a plane. Then, in the case of a transmissive liquid crystal display device, light from the backlight can pass through the substrate provided with the layers 125 and 126 having polarizers, and a predetermined video display is performed. In the case of a reflective liquid crystal display device, the reflected light passes through a substrate provided with a layer having a polarizer, whereby 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 121 side or the second substrate 122 side.

  As shown in FIG. 55B, when no voltage is applied between the first electrode 127 and the second electrode 128, black display is performed. At this time, the liquid crystal molecules 116 are arranged side by side. As a result, in the case of a transmissive liquid crystal display device, light from the backlight cannot pass through the substrate, resulting in black display. In the case of a reflective liquid crystal display device, a retardation plate is provided as necessary, and black display is achieved by shifting the phase by 90 ° including the liquid crystal layer.

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

  Next, an example in which the present invention is applied to a liquid crystal display device in an FFS (Fringe Field Switching) mode and an AFFS (Advanced Flying Field Switching) mode will be described.

  56A to 56B are schematic views of an AFFS mode liquid crystal display device.

  In the liquid crystal display devices in FIGS. 56A to 56B, the same components as those in FIGS. 44A to 44B are denoted by the same reference numerals. A first electrode 271, an insulating layer 273, and a second electrode 272 are provided over the second substrate 122. The first electrode 271 and the second electrode 272 have a light-transmitting property.

  As shown in FIG. 56A, when an applied voltage is applied to the first electrode 271 and the second electrode 272, a horizontal electric field 275 is generated. The liquid crystal molecules 116 rotate in the horizontal direction and pass light by becoming twisted. Since the rotation angles of the liquid crystal molecules are various, light incident obliquely passes therethrough. Then, in the case of a transmissive liquid crystal display device, light from the backlight can pass through the substrate provided with the layers 125 and 126 having polarizers, and a predetermined video display is performed. In the case of a reflective liquid crystal display device, the reflected light passes through a substrate provided with a layer having a polarizer, whereby 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 121 side or the second substrate 122 side.

  Then, as shown in FIG. 50B, when no voltage is applied between the first electrode 271 and the second electrode 272, black display, that is, an off state is obtained. At this time, the liquid crystal molecules 116 are arranged side by side and rotated in a plane. As a result, in the case of a transmissive liquid crystal display device, light from the backlight cannot pass through the substrate, resulting in black display. In the case of a reflective liquid crystal display device, a retardation plate is provided as necessary, and light from outside light passes through only a component of light that vibrates in the transmission axis direction of the polarizer and becomes linearly polarized light. Passes through the phase difference plate and becomes circularly polarized light (for example, right circularly polarized light). When the right circularly polarized light is reflected by the reflecting plate (or the reflecting electrode), it becomes left circularly polarized light. ) Is linearly polarized light that vibrates. Accordingly, the light is absorbed by the absorption axis of the polarizer, so that black display is obtained.

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

  FIGS. 57A to 57D illustrate examples of the first electrode 271 and the second electrode 272. 57A to 57D, the first electrode 271 is formed over the entire surface, and the second electrode 272 has various shapes. In FIG. 57A, the second electrode 272 has a structure in which strip-shaped electrodes are arranged obliquely. In FIG. 57B, the second electrode 272 has a partially circular shape. In FIG. 57C, the second electrode 272 is formed in a zigzag shape. In FIG. 57D, the second electrode 272 has a comb shape.

  In addition, the present invention can be applied to an optical rotation mode, a scattering mode, and a birefringence mode liquid crystal display device.

  Note that this embodiment can be implemented freely combining with any of the other embodiments and examples in this specification, if necessary.

[Embodiment 30]
In this embodiment, the liquid crystal display devices of the above-described fourth to fifteenth embodiments and twenty-fifth to twenty-eighth embodiments are replaced with a 2D / 3D switching type (two-dimensional / three-dimensional switching type) liquid crystal display panel. An example applied to is shown below.

  The structure of the 2D / 3D switching liquid crystal display panel of this embodiment is shown in FIG.

  As shown in FIG. 58, the 2D / 3D switching type liquid crystal display panel has a configuration in which a display liquid crystal panel 350, a phase difference plate 360, and a switching liquid crystal panel 370 are bonded together.

  The display liquid crystal panel 350 is provided as a TFT liquid crystal display panel, and includes a first polarizing plate 351, a counter substrate 352, a liquid crystal layer 353, an active matrix substrate 354, and a second polarizing plate 355, Image data corresponding to an image to be displayed is input to the active matrix substrate 354 via a wiring 381 such as an FPC (Flexible Printed Circuit).

  In other words, the display liquid crystal panel 350 is provided to give the 2D / 3D switching liquid crystal display panel a function of generating a display screen corresponding to the image data. Note that the display method (TN method or STN method) or driving method (active matrix driving or passive matrix driving) in the display liquid crystal panel 350 is not particularly limited as long as it has a function of generating a display screen. .

  The retardation plate 360 functions as a part of a parallax barrier, and has a configuration in which an alignment film is formed on a light-transmitting substrate and a liquid crystal layer is further stacked thereon.

  The switching liquid crystal panel 370 includes a driving side substrate 371, a liquid crystal layer 372, a counter substrate 373, and a third polarizing plate 374, and a driving voltage is applied to the driving side substrate 371 when the liquid crystal layer 372 is turned on. Wiring 382 is connected.

  The switching liquid crystal panel 370 is arranged to switch the polarization state of the light transmitted through the switching liquid crystal panel 370 in accordance with on / off of the liquid crystal layer 372. The switching liquid crystal panel 370 does not need to be matrix driven like the display liquid crystal panel 350, and the driving electrodes provided on the driving side substrate 371 and the counter substrate 373 are formed on the entire active area of the switching liquid crystal panel 370. Good.

  Next, the display operation of the 2D / 3D switching type liquid crystal display panel having the above configuration will be described.

  Incident light emitted from the light source is first polarized by the third polarizing plate 374 of the switching liquid crystal panel 370. The switching liquid crystal panel 370 functions as a phase difference plate (here, a half-wave plate) in an off state during 3D display.

  The light that has passed through the switching liquid crystal panel 370 is then incident on the phase difference plate 360. The phase difference plate 360 has a first region and a second region, and the rubbing directions of the first region and the second region are different. That the rubbing direction is different, that is, because the direction of the slow axis is different, the polarization state is different between the light passing through the first region and the light passing through the second region. For example, the polarization axes of the light passing through the first region and the light passing through the second region are different by 90 °. The retardation plate 360 is set to act as a half-wave plate by the birefringence anisotropy and the film thickness of the liquid crystal layer included in the retardation plate 360.

  The light that has passed through the retardation film 360 is incident on the second polarizing plate 355 of the display liquid crystal panel 350. At the time of 3D display, the polarization axis of the light that has passed through the first region of the retardation film 360 is parallel to the transmission axis of the second polarizing plate 355, and the light that has passed through the first region passes through the polarizing plate 355. . On the other hand, the polarization axis of the light that has passed through the second region forms an angle of 90 ° with the transmission axis of the second polarizing plate 355, and the light that has passed through the second region does not pass through the polarizing plate 355.

  That is, the function of the parallax barrier is achieved by the optical action related to the retardation plate 360 and the second polarizing plate 355, and the first region in the retardation plate 360 is a transmission region, and the second region is a blocking region. Become.

  The light that has passed through the second polarizing plate 355 is subjected to different optical modulation in the liquid crystal layer 353 of the display liquid crystal panel 350 between the pixel that performs black display and the pixel that performs white display, and is optically modulated by the pixel that performs white display. Only the received light is transmitted through the first polarizing plate 351, whereby image display is performed.

  At this time, the light passing through the transmission region of the parallax barrier or having a specific viewing angle passes through the pixels corresponding to the right-eye image and the left-eye image in the display liquid crystal panel 350, so that the right eye The image for use and the image for the left eye are separated into different viewing angles, and 3D display is performed.

  When 2D display is performed, the switching liquid crystal panel 370 is turned on, and no optical modulation is applied to the light passing through the switching liquid crystal panel 370. The light that has passed through the switching liquid crystal panel 370 then passes through the phase difference plate 360, so that different polarization states are given to the light that has passed through the first region and the light that has passed through the second region.

  However, in the case of 2D display, unlike the case of 3D display, since there is no optical modulation action in the switching liquid crystal panel 370, the polarization axis of the light that has passed through the phase difference plate 360 is transmitted by the second polarizing plate 355. A symmetric angle shift occurs with respect to the axis. Therefore, both the light that has passed through the first region and the light that has passed through the second region of the retardation plate 360 are transmitted through the second polarizing plate 355 with the same transmittance, and the retardation plate 360 and the second polarization plate are transmitted. The parallax barrier function due to the optical action associated with the plate 355 is not achieved (no specific viewing angle is given), resulting in a 2D display.

  Note that this embodiment can be implemented freely combining with any of the other embodiments and examples in this specification, if necessary.

[Embodiment 31]
As electronic devices to which the display device of the present invention is applied, a television device (also simply referred to as a television or a television receiver), a digital camera, a digital video camera, a mobile phone device (also simply referred to as a mobile phone or a mobile phone), a PDA Such as portable information terminals, portable game machines, computer monitors, computers, sound reproduction apparatuses such as car audio, and image reproduction apparatuses equipped with recording media such as home game machines. Specific examples thereof will be described with reference to FIGS. 65 (A) to 65 (F).

  A portable information terminal device illustrated in FIG. 65A includes a main body 1701, a display portion 1702, and the like. The display device of the present invention can be applied to the display portion 1702. As a result, a portable information terminal device with a high contrast ratio can be provided.

  A digital video camera shown in FIG. 65B includes a display portion 1711, a display portion 1712, and the like. The display device of the present invention can be applied to the display portion 1711. As a result, a digital video camera with a high contrast ratio can be provided.

  A cellular phone shown in FIG. 65C includes a main body 1721, a display portion 1722, and the like. The display device of the present invention can be applied to the display portion 1722. As a result, a mobile phone with a high contrast ratio can be provided.

  A portable television device shown in FIG. 65D includes a main body 1731, a display portion 1732, and the like. The display device of the present invention can be applied to the display portion 1732. 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. 65E includes a main body 1741, a display portion 1742, and the like. The display device of the present invention can be applied to the display portion 1742. As a result, a portable computer with a high contrast ratio can be provided.

  A television set shown in FIG. 65F includes a main body 1751, a display portion 1752, and the like. The display device of the present invention can be applied to the display portion 1752. As a result, a television device with a high contrast ratio can be provided.

  A detailed structure of the television set in FIG. 65F is shown in FIGS.

  FIG. 66 shows a liquid crystal module or a light-emitting display module (EL module) in which a display panel 1801 and a circuit board 1802 are combined. For example, a control circuit 1803, a signal dividing circuit 1804, and the like are formed on the circuit board 1802. The display panel 1801 and the circuit board 1802 are electrically connected by a connection wiring 1808.

  The display panel 1801 includes a pixel portion 1805, a scanning line driving circuit 1806, and a signal line driving circuit 1807 for supplying a video signal to a selected pixel, and this configuration is the same as that shown in FIGS. It is.

  With this liquid crystal module or light emitting display module, a liquid crystal television device or a light emitting display television device can be completed. FIG. 67 is a block diagram illustrating a main configuration of a liquid crystal television device or a light-emitting display television device. The tuner 1811 receives a video signal and an audio signal. The video signal includes a video wave amplifying circuit 1812, a video signal processing circuit 1813 that converts a signal output from the video wave amplifying circuit 1812 into color signals corresponding to each color of red, green, and blue, and the video signal as input specifications of the driver IC. Processing is performed by a control circuit 1803 for conversion. The control circuit 1803 outputs signals to the scanning line side and the signal line side, respectively. In the case of digital driving, a signal dividing circuit 1804 may be provided on the signal line side so that an input digital signal is divided into m pieces and supplied.

  Of the signals received by the tuner 1811, the audio signal is sent to the audio wave amplifier circuit 1814, and the output is supplied to the speaker 1816 via the audio signal processing circuit 1815. The control circuit 1817 receives control information on the receiving station (reception frequency) and volume from the input unit 1818 and sends a signal to the tuner 1811 and the audio signal processing circuit 1815.

  As shown in FIG. 68, a television set can be completed by incorporating a liquid crystal module or a light-emitting display module into a main body 1751. A display portion 1752 is formed using a liquid crystal module or a light-emitting display module. In addition, a speaker 1816, an operation switch 1819, and the like are provided as appropriate.

  By the present invention including the display panel 1801, a television device with a high contrast ratio can be obtained.

  Of course, the present invention is not limited to a television receiver, and is applied to various uses as a display medium of a particularly large area such as a monitor of a personal computer, an information display board in a railway station or airport, an advertisement display board in a street, etc. can do.

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

  This embodiment mode can be freely combined with any of the embodiment modes and examples if necessary.

  In this example, the result of optical calculation when polarizing plates having different extinction coefficients of absorption axes from each other when an electroluminescent element that emits light on both sides is assumed will be described. For comparison, optical calculation when one type of polarizing plate was used one by one and optical calculation when two types of one polarizing plate were used were also performed. The contrast ratio was the ratio of white transmittance to black transmittance (white transmittance / black transmittance), and the black transmittance and white transmittance were calculated to calculate the contrast ratio.

  The calculation in the present embodiment uses an optical calculation simulator LCD MASTER (manufactured by Shintech Co., Ltd.) for liquid crystal. When calculating the transmittance with respect to the wavelength using the LCD MASTER, the 2 × 2 matrix optical calculation algorithm that does not consider multiple interference between elements is used, and the light source wavelength is set at 10 nm intervals from 380 nm to 780 nm. Asked.

  In this example, polarizing plates A and B having different extinction coefficients were used. As the polarizing plate A, EG1425DU manufactured by Nitto Denko Corporation was used. As the polarizing plate B, SHC-PGW301 manufactured by Polatechno Co., Ltd. was used. FIG. 69 shows the wavelength dependence of the extinction coefficient of the absorption axis of each polarizing plate. It can be seen that the extinction coefficients of the respective polarizing plates are different. The thickness of each polarizing plate was 180 μm for both polarizing plates. A D65 light source was used as the backlight, and the polarization state was set to mixed circular polarization.

  Table 1 shows the wavelength dependence of the refractive index of the transmission axis and the absorption axis and the extinction coefficient of the transmission axis and the absorption axis of the polarizing plate A.

  Table 2 shows the wavelength dependency of the refractive index of the transmission axis and the absorption axis and the extinction coefficient of the transmission axis and the absorption axis of the polarizing plate B.

  In this example, as described above, the verification of the improvement of the contrast ratio when the polarizing plates are laminated using the two types of polarizing plates having different wavelength dependences of the extinction coefficients of the transmission axis and the absorption axis as described above. Do.

  The backlight wavelength and energy density are also shown in Table 3.

  Table 4 shows the optical system of black transmittance. The light emitting layer of the electroluminescent element must be provided between crossed Nicols whose polarizing axis absorption axis is 0 ° and 90 °, but the electroluminescent element is in a non-light emitting state during black display. A light emitting layer is not provided. In addition, since display under external light is assumed, a backlight is disposed instead of external light. As for the arrangement of the absorption axes of the polarizing plates, the absorption axes of the opposing polarizing plates shown in Table 4 were arranged in a crossed Nicol arrangement, and the polarizing plates to be laminated were parallel Nicols.

  In the optical system arranged in this way, the transmittance for the backlight on the viewing side opposite to the backlight was calculated. The polarizing plate has a structure 1 using one polarizing plate A, a structure 2 using two sets of two polarizing plates A, and a structure using two sets of one polarizing plate A and one polarizing plate B. The calculation was performed for 3.

  Table 5 shows the optical system of white transmittance. A backlight was used in place of the light emitting layer from the electroluminescence device. Therefore, a polarizing plate is arranged on the backlight which is a light emitting layer, and the laminated polarizing plate is parallel Nicol. In the optical system arranged in this way, transmittance was calculated for the backlight on the viewing side opposite to the backlight. In the white transmittance optical system, no light source serving as external light is disposed. This is because the result of black transmittance, which will be described later, was lower than the result of white transmittance, and therefore the result of white transmittance is regarded as having no influence of external light.

  As for the polarizing plate, the calculation was performed for the structure 4 in which one polarizing plate A was used, the structure 5 in which two polarizing plates A were stacked, and the structure 6 in which polarizing plates A and B were stacked one by one.

  FIG. 70 shows the calculation result of the black transmittance in the arrangement of Table 4. From this, when two sets of two polarizing plates A laminated are used (two polarizing plates A × 2) than when using one polarizing plate A (one polarizing plate A × 1). The transmittance is low in the entire wavelength region from 380 nm to 780 nm. Furthermore, when two sets in which two polarizing plates A are stacked (two polarizing plates A × two) are used, two sets in which one polarizing plate A and one polarizing plate B are stacked (polarizing plate It can be seen that A and B each have a lower transmittance in the entire wavelength region. This is because the polarizing plate B has a larger extinction coefficient of the absorption axis than the polarizing plate A, and light leakage can be reduced by laminating polarizing plates having different extinction coefficients of the absorption axes. Means that

  Furthermore, the ratio (white transmittance / black transmittance) between the white transmittance with the arrangement shown in Table 5 and the black transmittance with the arrangement shown in Table 4 was calculated. The contrast ratio when the polarizing plate A is used one by one is the ratio of the transmittance of the structure 4 to the transmittance of the structure 1 and the contrast ratio when two pairs of two polarizing plates A are stacked is the structure 5 The ratio of the transmittance of the structure 6 and the transmittance of the structure 3 when using two sets of the polarizing plates A and B laminated one by one. And the ratio.

  The calculation result of the contrast ratio is shown in FIG. Accordingly, the contrast ratio is higher in the entire wavelength region from 380 nm to 780 nm for the two polarizing plates A × 2 than for the polarizing plate A1 × 1. Furthermore, it can be seen that each of the polarizing plates A and B × 2 sheets has a higher contrast ratio in the entire wavelength region than the polarizing plates A2 × 2. This is because the black transmittance is lowered by laminating polarizing plates having different absorption coefficients of absorption axes.

  Regarding the two sets in which the polarizing plate A and the polarizing plate B are laminated one by one, in the black transmittance optical system, combinations shown in Table 6 other than the structure 3 (structures 7, 8, and 9) are considered. It is done. Further, in the white transmittance optical system, the structure 10 shown in Table 7 can be considered in addition to the structure 6. The black transmittance and the white transmittance in these structures are the same as those in the structures 3 and 6, and any combination can achieve high contrast.

  From the above results, it is possible to reduce the light leakage by laminating the polarizing plates having different extinction coefficients of the absorption axes, so that the contrast ratio can be improved.

  In this embodiment, when an electroluminescent element that emits light on both sides is assumed, a structure including a retardation plate (in this embodiment, a quarter-wave plate is used, hereinafter referred to as a “λ / 4 plate”) is mutually absorbed. The result of optical calculation when polarizing plates having different axial extinction coefficients will be described. For comparison, optical calculation when one type of polarizing plate was used one by one and optical calculation when two types of one polarizing plate were used were also performed. The contrast ratio was the ratio of white transmittance to black transmittance (white transmittance / black transmittance), and the black transmittance and white transmittance were calculated to calculate the contrast ratio.

  The calculation in the present embodiment uses an optical calculation simulator LCD MASTER (manufactured by Shintech Co., Ltd.) for liquid crystal. When calculating the transmittance with respect to the wavelength using the LCD MASTER, the 2 × 2 matrix optical calculation algorithm that does not consider multiple interference between elements is used, and the light source wavelength is set at 10 nm intervals from 380 nm to 780 nm. Asked.

  The same polarizing plate A and polarizing plate B as in Example 1 were used. FIG. 72 shows the wavelength dependence of the extinction coefficient of the absorption axis of each polarizing plate. It can be seen that the extinction coefficients of the respective polarizing plates are different. The thickness of each polarizing plate was 180 μm for both polarizing plates. A D65 light source was used as the backlight, and the polarization state was set to mixed circular polarization. As the λ / 4 plate, a retardation plate having a retardation of 137.5 nm in the entire wavelength region of 380 nm to 780 nm was used. The thickness of the λ / 4 plate was 100 μm.

  Table 8 shows the wavelength dependence of the refractive index in the x, y, and z directions of the λ / 4 plate. Hereinafter, in this example, calculation was performed using a retardation plate having the characteristics shown in Table 8.

  Table 9 shows the optical system of black transmittance. Since the black display in the electroluminescence element is a non-light emitting state, the light emitting layer of the electroluminescence element is not provided between the λ / 4 plates. In addition, since display under external light is assumed, a backlight is disposed instead of external light. The arrangement of the slow axis of the λ / 4 plate and the absorption axis of the polarizing plate is such that the slow axes of the λ / 4 plate shown in Table 9 (A) are shifted by 90 degrees, and the absorption axes of the opposing polarizing plates are crossed Nicols. Laminate the polarizing plates to be arranged in parallel Nicols, and the slow axes of the λ / 4 plates shown in Table 9 (B) are parallel to each other, the absorption axes of the opposing polarizing plates are arranged in parallel Nicols, and laminated. The polarizing plate was parallel Nicol.

  In the optical system arranged in this way, the transmittance for the backlight on the viewing side opposite to the backlight was calculated. The polarizing plate is a structure 1 and a structure 4 using one polarizing plate A, a structure 2 and a structure 5 using two sets of two polarizing plates A, and a polarizing plate A and a polarizing plate B are stacked one by one. Calculations were made for Structure 3 and Structure 6 using two sets.

  Table 10 shows the optical system of white transmittance. A backlight was used instead of light emission from the electroluminescence element. Therefore, a pair of λ / 4 plates as shown in Table 9 were not arranged, a λ / 4 plate was arranged on the backlight, and a polarizing plate was arranged on the λ / 4 plate.

  At this time, the absorption axis of the polarizing plate is arranged to deviate by 45 degrees with respect to the slow axis of the λ / 4 plate. The polarizing plate to be laminated was parallel Nicol. In the optical system arranged in this way, transmittance was calculated for the backlight on the viewing side opposite to the backlight. In the white transmittance optical system, no light source serving as external light is disposed. This is because the result of black transmittance, which will be described later, was lower than the result of white transmittance, and therefore the result of white transmittance is regarded as having no influence of external light.

  As for the polarizing plate, calculation was performed for the structure 7 using one polarizing plate A, the structure 8 in which two polarizing plates A were stacked, and the structure 9 in which polarizing plates A and B were stacked one by one. In addition, since the optical arrangement of the white transmittance shown in Table 10 is arranged by shifting the absorption axis of the polarizing plate by 45 degrees with respect to the slow axis of the λ / 4 plate, Table 9 (A) and Table 9 (B ) The white transmittance in both cases is calculated.

  FIG. 73 shows the calculation result of the black transmittance in the arrangement shown in Table 9 (A). From this, when two sets of two polarizing plates A laminated are used (two polarizing plates A × 2) than when using one polarizing plate A (one polarizing plate A × 1). The transmittance is low in the entire wavelength region from 380 nm to 780 nm. Furthermore, when two sets in which two polarizing plates A are stacked (two polarizing plates A × two) are used, two sets in which one polarizing plate A and one polarizing plate B are stacked (polarizing plate It can be seen that A and B each have a lower transmittance in the entire wavelength region. This is because the polarizing plate B has a larger extinction coefficient of the absorption axis than the polarizing plate A, and light leakage can be reduced by laminating polarizing plates having different extinction coefficients of the absorption axes. Means that

  FIG. 74 shows the calculation result of the black transmittance in the arrangement shown in Table 9 (B). From this, when two sets of two polarizing plates A laminated are used (two polarizing plates A × 2) than when using one polarizing plate A (one polarizing plate A × 1). The transmittance is low in the entire wavelength region from 380 nm to 780 nm. Furthermore, when two sets in which two polarizing plates A are stacked (two polarizing plates A × two) are used, two sets in which one polarizing plate A and one polarizing plate B are stacked (polarizing plate It can be seen that A and B each have a lower transmittance in the short wavelength region. This is because the polarizing plate B has a larger extinction coefficient of the absorption axis than the polarizing plate A, and light leakage can be reduced by laminating polarizing plates having different extinction coefficients of the absorption axes. Means that

  Comparing FIG. 73 and FIG. 74, the black transmittance is lower in the wider wavelength region when the opposing polarizing plates are arranged in crossed Nicols. On the other hand, when the opposing polarizing plates are arranged in parallel Nicols, the black transmittance is low only in the vicinity of the wavelength of 380 nm and in the vicinity of the wavelength of 550 nm.

Furthermore, the ratio (white transmittance / black transmittance) of the white transmittance with the arrangement shown in Table 10 and the black transmittance with the arrangement shown in Table 9 was calculated. The contrast ratio when the polarizing plates A are used one by one is the ratio between the transmittance of the structure 7 and the transmittance of the structure 1 or the structure 4, and when two sets of two polarizing plates A are stacked are used. The contrast ratio is the ratio between the transmittance of the structure 8 and the transmittance of the structure 2 or the structure 5. The contrast ratio when two sets of the polarizing plates A and B are laminated one by one is used. This is the ratio between the transmittance and the transmittance of structure 3 or structure 6.

  FIG. 75 shows the calculation result of the contrast ratio when the black transmittance is in Table 9 (A). Accordingly, the contrast ratio is higher in the entire wavelength region from 380 nm to 780 nm for the two polarizing plates A × 2 than for the polarizing plate A1 × 1. Furthermore, it can be seen that each of the polarizing plates A and B × 2 sheets has a higher contrast ratio in the entire wavelength region than the polarizing plates A2 × 2. This is because the black transmittance is lowered by laminating polarizing plates having different absorption coefficients of absorption axes.

  FIG. 76 shows the calculation result of the contrast ratio when the black transmittance is Table 9 (B). Accordingly, the contrast ratio is higher in the entire wavelength region from 380 nm to 780 nm for the two polarizing plates A × 2 than for the polarizing plate A1 × 1. Furthermore, it can be seen that each of the polarizing plates A and B × 2 sheets has a higher contrast ratio in the entire wavelength region than the polarizing plates A2 × 2. This is because the black transmittance is lowered by laminating polarizing plates having different absorption coefficients of absorption axes.

  When FIG. 75 and FIG. 76 are compared, the contrast ratio is higher in a wider wavelength region when the opposing polarizing plates are arranged in crossed Nicols. On the other hand, when the opposing polarizing plates are arranged in parallel Nicols, the contrast ratio is high only in the vicinity of the wavelength of 380 nm and in the vicinity of the wavelength of 550 nm.

  This can be said that the difference in the black transmittance appears in the contrast ratio because the polarizing plates facing each other in the white transmittance are the same both in the crossed Nicols arrangement and in the parallel Nicols arrangement.

  Regarding the two sets in which the polarizing plate A and the polarizing plate B are laminated one by one, in the black transmittance optical system, combinations shown in Table 11 other than the structure 3 (structures 10, 11, and 12) are considered. It is done. Further, in the optical system of white transmittance, in addition to the structure 9, a structure 13 shown in Table 12 can be considered. The black transmittance and the white transmittance in these structures are the same as those of the structures 3 and 9, and any combination can achieve high contrast.

  From the above results, it is possible to reduce the light leakage by laminating the polarizing plates having different extinction coefficients of the absorption axes, so that the contrast ratio can be improved. Note that the opposing polarizing plates preferably have a crossed Nicols arrangement, and a high contrast ratio can be obtained over a wide band.

FIG. 6 illustrates a display device of the present invention. The figure which shows the structure of the laminated | stacked polarizer of this invention. FIG. 6 illustrates a display device of the present invention. The figure which shows the angle | corner which the polarizer of this invention makes. FIG. 6 illustrates a display device of the present invention. Sectional drawing of the display apparatus of this invention. Sectional drawing of the display apparatus of this invention. FIG. 6 illustrates a display device of the present invention. Sectional drawing of the display apparatus of this invention. Sectional drawing of the display apparatus of this invention. The figure which showed the illumination means which the display apparatus of this invention has. The figure which showed the illumination means which the display apparatus of this invention has. The figure which showed the illumination means which the display apparatus of this invention has. FIG. 6 illustrates a display device of the present invention. Sectional drawing of the display apparatus of this invention. Sectional drawing of the display apparatus of this invention. FIG. 6 illustrates a display device of the present invention. Sectional drawing of the display apparatus of this invention. Sectional drawing of the display apparatus of this invention. 1 is a block diagram illustrating a display device of the present invention. 1 is a block diagram illustrating a display device of the present invention. FIG. 6 illustrates a display device of the present invention. Sectional drawing of the display apparatus of this invention. FIG. 6 illustrates a display device of the present invention. The figure which shows the angle | corner which the polarizer of this invention makes. Sectional drawing of the display apparatus of this invention. FIG. 6 illustrates a display device of the present invention. The figure which shows the angle | corner which the polarizer of this invention makes. Sectional drawing of the display apparatus of this invention. FIG. 6 illustrates a display device of the present invention. Sectional drawing of the display apparatus of this invention. 1 is a block diagram illustrating a display device of the present invention. FIG. 6 illustrates a display device of the present invention. The figure which shows the angle | corner which the polarizer of this invention makes. FIG. 6 illustrates a display device of the present invention. FIG. 6 illustrates a display device of the present invention. FIG. 6 illustrates a pixel circuit included in a display device of the present invention. FIG. 6 illustrates a display device of the present invention. FIG. 6 illustrates a display device of the present invention. The figure which shows the angle | corner which the polarizer of this invention makes. FIG. 6 illustrates a display device of the present invention. FIG. 6 illustrates a display device of the present invention. The figure which shows the angle | corner which the polarizer of this invention makes. The figure which showed the mode of the liquid crystal element of this invention. The figure which showed the mode of the liquid crystal element of this invention. The figure which showed the mode of the liquid crystal element of this invention. The figure which showed the mode of the liquid crystal element of this invention. FIG. 6 is a top view illustrating one pixel of the display device of the present invention. The figure which showed the mode of the liquid crystal element of this invention. The figure which showed the mode of the liquid crystal element of this invention. FIG. 6 shows an electrode for driving liquid crystal molecules of a display device of the present invention. FIG. 6 is a top view illustrating one pixel of the display device of the present invention. The figure which showed the mode of the liquid crystal element of this invention. FIG. 6 is a top view illustrating one pixel of the display device of the present invention. The figure which showed the mode of the liquid crystal element of this invention. The figure which showed the mode of the liquid crystal element of this invention. FIG. 6 shows an electrode for driving liquid crystal molecules of a display device of the present invention. 1 is a diagram showing a 2D / 3D switching liquid crystal display panel having a display device of the present invention. The figure which shows the structure of the laminated | stacked polarizer of this invention. The figure which shows the structure of the laminated | stacked polarizer of this invention. The figure which shows the structure of the laminated | stacked polarizer of this invention. The figure which shows the structure of the laminated | stacked polarizer of this invention. The figure which shows the structure of the laminated | stacked polarizer of this invention. The figure which shows the structure of the laminated | stacked polarizer of this invention. FIG. 16 illustrates an electronic device having a display device of the invention. FIG. 16 illustrates an electronic device having a display device of the invention. FIG. 16 illustrates an electronic device having a display device of the invention. FIG. 16 illustrates an electronic device having a display device of the invention. The figure which showed the extinction coefficient of the polarizing plate of Example 1. FIG. The figure which showed the calculation result of Example 1. FIG. The figure which showed the calculation result of Example 1. FIG. The figure which showed the extinction coefficient of the polarizing plate of Example 2. FIG. The figure which showed the calculation result of Example 2. FIG. The figure which showed the calculation result of Example 2. FIG. The figure which showed the calculation result of Example 2. FIG. The figure which showed the calculation result of Example 2. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Display element 101 Substrate 102 Substrate 103 Polarizer 104 Polarizer 111 Substrate 112 Substrate 113 Polarizing plate 114 Polarizing plate 116 Liquid crystal molecule 118 Protrusion 119 Slit 120 Layer having liquid crystal element 121 Substrate 122 Substrate 125 Layer 126 having polarizer Layer 127 electrode 128 electrode 131 adhesive layer 132 protective film 133 polarizing film 135 adhesive layer 136 protective film 137 polarizing film 140 adhesive layer 141 adhesive layer 142 protective film 143 polarizing film 144 polarizing film 145 polarizing plate 146 protective film 147 polarizing film 148 polarizing Film 149 Polarizing plate 151 Absorption axis 152 Absorption axis 155 Electrode 156 Electrode 158 Polarizing film 159 Polarizing film 160 Layer having liquid crystal element 161 Substrate 162 Substrate 163 Polarizing plate 165 Polarizing plate 166 Polarizing plate 168 Polarizing film 169 Polarizing plate 171 Feedboard 172 retardation plate 173 groove 174 groove 176 layer 181 absorption axis 182 absorption axis 183 absorption axis 184 absorption axis 186 slow axis 187 slow axis 191 TFT having a display device
192 Gate wiring 193 Island-like semiconductor film 196 Drain electrode 197 Source electrode 198 Source wiring 199 Pixel electrode 200 Display element 201 Substrate 202 Substrate 203 Polarizer 204 Polarizer 206 Groove 207 Groove 208 Auxiliary capacitor 211 Retardation plate 215 Polarizing film 216 Polarizing film 217 Polarizing plate 221 Absorption axis 222 Absorption axis 223 Slow axis 225 Polarizing film 226 Polarizing film 227 Polarizing film 231 TFT
232 Gate wiring 233 Common wiring 234 Contact hole 235 Source wiring 236 Drain electrode 237 Island-like semiconductor film 238 Source electrode 241 Pixel electrode 242 Common electrode 251 TFT
252 Gate wiring 253 Island-like semiconductor film 256 Drain electrode 257 Source electrode 259 Pixel electrode 263 Groove 265 Projection 267 Auxiliary capacitance 271 Electrode 272 Electrode 273 Insulating layer 275 Electric field 300 Layer having liquid crystal element 301 Substrate 302 Substrate 303 Polarizer 304 Polarizer 305 Polarizing plate 306 Polarizing plate 321 Absorption axis 322 Absorption axis 323 Absorption axis 324 Absorption axis 350 Display liquid crystal panel 351 Polarizing plate 352 Opposing substrate 353 Liquid crystal layer 354 Active matrix substrate 355 Polarizing plate 360 Phase difference plate 370 Switching liquid crystal panel 371 Driving side substrate 372 Liquid crystal layer 373 Counter substrate 374 Polarizing plate 381 Wiring 382 Wiring 401 Video signal 402 Control circuit 403 Signal line driving circuit 404 Scanning line driving circuit 405 Pixel unit 406 Illuminating means 408 Driving circuit unit 410 Scanning line 12 signal line 421 IC
422 conductive fine particles 431 shift register 432 latch 433 latch 434 level shifter 435 buffer 441 shift register 442 level shifter 443 buffer 501 substrate 502 base film 503 switching TFT
504 Capacitor element 505 Interlayer insulating film 506 Pixel electrode 507 Protective film 508 Alignment film 510 Connection terminal 511 Liquid crystal 516 Stacked polarizing plate 520 Counter substrate 521 Stacked polarizing plate 522 Color filter 523 Counter electrode 524 Black matrix 525 Spacer 526 Alignment film 528 Sealing material 531 Light source 532 Lamp reflector 533 Switching TFT
534 Reflecting plate 535 Light guiding plate 536 Diffusing plate 537 Bump 541 Polarizing plate 542 Polarizing plate 543 Polarizing plate 544 Polarizing plate 546 Phase difference plate 547 Phase difference plate 552 Backlight unit 554 CMOS circuit 571 Cold cathode tube 572 Diode (W)
573 Diode (R)
574 Diode (G)
575 Diode (B)
600 Layer having liquid crystal element 601 Substrate 602 Substrate 603 Polarizing plate 604 Polarizing plate 621 Retardation plate 651 Absorption axis 652 Absorption axis 653 Slow axis 701 Substrate 702 Base film 703 Switching TFT
704 Capacitor element 705 Interlayer insulating film 706 Pixel electrode 707 Protective film 708 Alignment film 710 Connection terminal 711 Liquid crystal 716 Phase difference plate 717 Polarization plate 718 Polarization plate 720 Counter substrate 722 Color filter 723 Counter electrode 724 Black matrix 725 Spacer 726 Alignment film 728 Sealing Stopping material 733 Switching TFT
741 Phase difference plate 742 Polarization plate 743 Polarization plate 754 CMOS circuit 800 Layer having liquid crystal element 801 Substrate 802 Substrate 803 Polarization plate 804 Polarization plate 811 Pixel electrode 812 Counter electrode 821 Phase difference plate 825 Phase difference plate 826 Polarization plate 827 Polarization plate 831 Pixel electrode 832 Counter electrode 841 Retardation plate 842 Polarizing plate 843 Polarizing plate 851 Absorption axis 852 Absorption axis 853 Slow axis 1100 Layer having electroluminescence element 1101 Substrate 1102 Substrate 1111 Polarizing plate 1112 Polarizing plate 1121 Polarizing plate 1122 Polarizing plate 1131 Lamination Laminated polarizing plate 1132 laminated polarizing plate 1151 absorption axis 1152 absorption axis 1153 absorption axis 1154 absorption axis 1201 substrate 1203 thin film transistor 1204 thin film transistor 1205 insulating layer 1206 electrode 1207 electroluminescence 1208 Electrode 1209 Light-emitting element 1210 Insulating layer 1214 Capacitor element 1215 Pixel portion 1216 Polarizing plate 1217 Polarizing plate 1218 Driving circuit portion 1218a Signal line driving circuit portion 1218b Scanning line driving circuit portion 1219 Stacked polarizing plate 1220 Counter substrate 1225 Phase difference plate 1226 Polarizing plate 1227 Polarizing plate 1228 Sealing material 1229 Laminated polarizing plate 1235 Retardation plate 1241 Electrode 1242 Electrode 1251 Electrode 1252 Electrode 1300 Layer having electroluminescence element 1301 Substrate 1302 Substrate 1311 Polarizing plate 1312 Polarizing plate 1313 Retardation plate 1315 Laminating Polarized polarizing plate 1321 Polarizing plate 1322 Polarizing plate 1323 Retardation plate 1325 Laminated polarizing plate 1331 Slow axis 1332 Slow axis 1335 Absorption axis 1336 Absorption axis 1337 Absorption axis 1338 Absorption axis 1351 Shift register 1354 Level shifter 1355 Buffer 1361 Shift register 1362 Latch circuit 1363 Latch circuit 1364 Level shifter 1365 Buffer 1371 Scan line 1372 Signal line 1380 Transistor 1381 Transistor 1382 Capacitance element 1383 Light emitting element 1384 Signal line 1385 Power line 1386 Scan line 1388 Transistor 1389 Scanning line 1395 Transistor 1396 Wiring 1400 Electroluminescent element layer 1401 Substrate 1402 Substrate 1403 Polarizing plate 1404 Polarizing plate 1421 Retardation plate 1451 Absorption axis 1452 Absorption axis 1453 Slow axis 1460 Layer 1Display substrate 1461 Substrate 1462 Substrate 1471 Polarizing plate 1472 Polarizing plate 1473 Retardation plate 1475 Laminated polarizing plate 481 Polarizing plate 1482 Polarizing plate 1483 Retardation plate 1485 Laminated polarizing plate 1491 Slow axis 1492 Slow axis 1495 Absorption axis 1496 Absorption axis 1497 Absorption axis 1498 Absorption axis 1500 Layer having electroluminescence element 1501 Substrate 1502 Substrate 1503 Polarizing plate 1504 Polarizing plate 1521 Retardation plate 1551 Absorption axis 1552 Absorption axis 1553 Slow axis 1560 Layer 1561 with display element Substrate 1562 Substrate 1575 Retardation plate 1571 Polarizing plate 1572 Polarizing plate 1573 Laminated polarizing plate 1576 Retardation plate 1581 Polarizing plate 1582 Polarizing plate 1583 Laminated polarizing plate 1591 Slow axis 1592 Slow axis 1595 Absorption axis 1596 Absorption axis 1597 Absorption axis 1598 Absorption axis 1600 Display element layer 1601 Substrate 1602 Substrate 1611 Polarization 1612 Polarizing plate 1613 Laminated polarizing plate 1621 Polarizing plate 1622 Polarizing plate 1623 Laminated polarizing plate 1631 Absorption axis 1632 Absorption axis 1633 Absorption axis 1634 Absorption axis 1660 Layer having display element 1661 Substrate 1662 Substrate 1675 Retardation plate 1671 Polarizing plate 1672 Polarizing plate 1673 Laminated polarizing plate 1676 Retardation plate 1681 Polarizing plate 1682 Polarizing plate 1683 Laminated polarizing plate 1691 Slow axis 1692 Slow axis 1695 Absorption axis 1696 Absorption axis 1697 Absorption axis 1698 Absorption axis 1701 Main body 1702 Display unit 1711 Display unit 1712 Display unit 1721 Main unit 1722 Display unit 1731 Main unit 1732 Display unit 1741 Main unit 1742 Display unit 1751 Main unit 1752 Display unit 1801 Display panel 1802 Circuit board 1803 Control circuit 180 Signal dividing circuit 1805 Pixel unit 1806 Scanning line driving circuit 1807 Signal line driving circuit 1808 Connection wiring 1811 Tuner 1812 Video wave amplification circuit 1813 Video signal processing circuit 1814 Audio wave amplification circuit 1815 Audio signal processing circuit 1816 Speaker 1817 Control circuit 1818 Input unit 1819 Operation switch

Claims (10)

  1. A first substrate;
    A second substrate;
    A layer having a display element sandwiched between the first substrate and the second substrate;
    A polarizer laminated on the outside of the first substrate or the second substrate;
    Have
    The stacked polarizers are arranged so that their absorption axes are parallel Nicols, and have different extinction coefficients.
  2. A first substrate;
    A second substrate;
    A layer having a display element sandwiched between the first substrate and the second substrate;
    A polarizer laminated on the outside of the first substrate;
    A polarizer laminated on the outside of the second substrate;
    Have
    The polarizers stacked on the outside of the first substrate are arranged so that their absorption axes are parallel Nicols, and the extinction coefficients are different from each other.
    The polarizers laminated on the outside of the second substrate are arranged so that their absorption axes are parallel Nicols, and the extinction coefficients are different from each other.
    The absorption axis of the polarizer laminated on the outside of the first substrate and the absorption axis of the polarizer laminated on the outside of the second substrate are arranged so as to be crossed Nicols. Display device.
  3. A first substrate;
    A second substrate;
    A layer having a display element sandwiched between the first substrate and the second substrate;
    A polarizer laminated on the outside of the first substrate;
    A polarizer laminated on the outside of the second substrate;
    Have
    The polarizers stacked on the outside of the first substrate are arranged so that their absorption axes are parallel Nicols, and the extinction coefficients are different from each other.
    The polarizers laminated on the outside of the second substrate are arranged so that their absorption axes are parallel Nicols, and the extinction coefficients are different from each other.
    The absorption axis of the polarizer laminated on the outside of the first substrate and the absorption axis of the polarizer laminated on the outside of the second substrate are arranged so as to be parallel Nicols. Display device.
  4. A first substrate;
    A second substrate;
    A layer having a display element sandwiched between the first substrate and the second substrate;
    A polarizer laminated on the outside of the first substrate or the second substrate;
    A retardation plate between the first substrate or the second substrate and the laminated polarizer;
    Have
    The stacked polarizers are arranged so that their absorption axes are parallel Nicols, and have different extinction coefficients.
  5. A first substrate;
    A second substrate;
    A layer having a display element sandwiched between the first substrate and the second substrate;
    A polarizer laminated on the outside of the first substrate;
    A polarizer laminated on the outside of the second substrate;
    Between the first substrate and a polarizer laminated outside the first substrate, a first retardation plate,
    A second retardation plate between the second substrate and a polarizer laminated outside the second substrate;
    Have
    The polarizers stacked on the outside of the first substrate are arranged so that their absorption axes are parallel Nicols, and the extinction coefficients are different from each other.
    The polarizers laminated on the outside of the second substrate are arranged so that their absorption axes are parallel Nicols, and the extinction coefficients are different from each other.
    The absorption axis of the polarizer laminated on the outside of the first substrate and the absorption axis of the polarizer laminated on the outside of the second substrate are arranged so as to be crossed Nicols. Display device.
  6. A first substrate;
    A second substrate;
    A layer having a display element sandwiched between the first substrate and the second substrate;
    A polarizer laminated on the outside of the first substrate;
    A polarizer laminated on the outside of the second substrate;
    Between the first substrate and a polarizer laminated outside the first substrate, a first retardation plate,
    A second retardation plate between the second substrate and a polarizer laminated outside the second substrate;
    Have
    The polarizers stacked on the outside of the first substrate are arranged so that their absorption axes are parallel Nicols, and the extinction coefficients are different from each other.
    The polarizers laminated on the outside of the second substrate are arranged so that their absorption axes are parallel Nicols, and the extinction coefficients are different from each other.
    The absorption axis of the polarizer laminated on the outside of the first substrate and the absorption axis of the polarizer laminated on the outside of the second substrate are arranged so as to be parallel Nicols. Display device.
  7. In claim 4,
    The display device, wherein an absorption axis of the laminated polarizer and a slow axis of the retardation plate are arranged to be shifted by 45 °.
  8. In claim 5 or claim 6,
    The absorption axis of the polarizer laminated on the outside of the first substrate and the slow axis of the first retardation plate are arranged to be shifted by 45 °,
    The display device, wherein an absorption axis of a polarizer laminated on the outside of the second substrate and a slow axis of the second retardation plate are arranged to be shifted by 45 °.
  9. In any one of Claims 1 thru | or 8,
    The display device, wherein the display element is a liquid crystal element.
  10. In any one of Claims 1 thru | or 8,
    The display device is an electroluminescence element.
JP2007016980A 2006-02-02 2007-01-26 Display device Withdrawn JP2007233361A (en)

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JP2012068438A (en) * 2010-09-24 2012-04-05 Konica Minolta Opto Inc LONG-SHAPE λ/4 PLATE, CIRCULAR POLARIZER, POLARIZER, OLED DISPLAY DEVICE, AND THREE-DIMENSIONAL IMAGE DISPLAY DEVICE

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