JP4122926B2 - Liquid crystal display device and electronic device - Google Patents

Description

【００４１】
【表２】

【００４２】
（実施例２）
次に、図１に示す液晶表示装置において、下反射偏光層６の誘電体積層膜４０を構成する各誘電体膜４１の膜厚を種々に変えたサンプルを作製して、その反射表示の視認性を検証した。本例において作製した液晶表示装置は、上記実施例１と同様に図１に示す基本構成を備え、誘電体積層膜４０の層構成を表３に示す構成としたものである。また、各サンプルにおいて、凸条４２の谷線部における誘電体積層膜４０の膜厚ａ、及び稜線部における膜厚ｂは、表４に示す組み合わせとした。尚、各サンプルの作製方法は上記実施例１と同様である。
【００４３】
次に、上記工程により得られた層構成１〜３のサンプルの液晶表示装置を動作させ、反射モードの白表示について目視観察して色付き及び視角特性について評価した。その結果を表４に併記する。
表４に示すように、本実施例のサンプルにおいては、凸条４２の谷線部における誘電体積層膜４０の膜厚ａと、稜線部における膜厚ｂとの比ａ／ｂはいずれも０．８以下とされており、いずれも色付きが小さく、また視角依存性も小さくなっており良好な反射表示が得られていたが、表３に示す層厚構成３のサンプルでは、特に色付きが皆無で、視角依存性もほぼない極めて良好な表示を実現していた。
この層厚構成３のサンプルは誘電体積層膜４０の第２層が１０．１ｎｍとされたものであるが、同じく第２層が２１．６ｎｍと薄くされた層構成２のサンプルに比しても極めて良好な表示が得られており、このことから誘電体積層膜を構成する誘電体膜４１のうち少なくとも１層を１５ｎｍ以下の膜厚とするならば、表示の色付き及び視角特性を著しく改善できることが示唆される。
【００４４】
【表３】

【００４５】
【表４】

【図面の簡単な説明】
【図１】 図１は、本発明の第１の実施形態である半透過反射型液晶表示装置の部分断面構造を示す図である。
【図２】 図２は、図１に示す下反射偏光層を拡大して示す部分断面図である。
【図３】 図３は、図２に示す凸条の１つを拡大して示す部分断面図である。
【図４】 図４は、図１に示す液晶表示装置の動作を説明するための説明図である。
【図５】 図５は、本発明の第２の実施形態である半透過反射型液晶表示装置の部分断面構造を示す図である。
【図６】 図６は、図５に示す液晶表示装置の動作を説明するための説明図である。
【図７】 図７は、本発明に係る電子機器の一例を示す斜視構成図である。
【符号の説明】
１ 液晶表示装置、２ 下基板、３ 上基板、４ 液晶層、５ バックライト、６，３６ 下反射偏光層、１１ カラーフィルタ、１３ 上偏光板（上偏光層）、１６ 前方散乱板、２０ 下偏光板（下偏光層）[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a liquid crystal display device and an electronic apparatus, and more particularly to a configuration of a reflective polarizing layer of a liquid crystal display device.
[0002]
[Prior art]
Reflective liquid crystal display devices have low power consumption because they do not have a light source such as a backlight, and are conventionally widely used in various portable electronic devices and display units attached to devices. However, since the display is performed using external light such as natural light or illumination light, there is a problem that it is difficult to visually recognize the display in a dark place. Therefore, a liquid crystal display device has been proposed in which outside light is used in a bright place in the same manner as a normal reflection type liquid crystal display device, but in a dark place, the display can be visually recognized by an internal light source. In other words, this liquid crystal display device employs a display method that combines a reflective type and a transmissive type, and reduces power consumption by switching to either the reflective mode or the transmissive mode depending on the ambient brightness. However, a clear display can be performed even when the surroundings are dark. Hereinafter, in this specification, this type of liquid crystal display device is referred to as a “semi-transmissive reflection type liquid crystal display device”. As a transflective plate used for a transflective liquid crystal display device, for example, a metal film provided with an opening for transmitting light, or a part of incident light is reflected by, for example, adjusting the film thickness, and a part is transmitted. Membranes, so-called half mirrors and the like have been used conventionally.
[0003]
Conventionally, a dielectric multilayer film formed on the surface of a prism is a semi-transmissive film, and a polarized beam splitter (hereinafter abbreviated as PBS) that separates incident light into two linearly polarized lights whose polarization directions are orthogonal to each other. Is known). Then, it has been proposed to use a PBS array in which a plurality of these are arranged in an array as a reflective polarizing plate (for example, Patent Document 1). A liquid crystal display device in which this PBS array is disposed between a liquid crystal panel and a backlight has been proposed (for example, Patent Document 2). According to this liquid crystal display device, among the light emitted from the backlight, one linearly polarized light separated by the PBS array is emitted toward the liquid crystal panel, while the other linearly polarized light is reflected to the backlight side. A liquid crystal display device with high light use efficiency can be realized by returning and using the light source light again.
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 5-19208
[Patent Document 2]
Japanese Patent Laid-Open No. 7-64085
[0005]
[Problems to be solved by the invention]
By the way, the above-mentioned PBS array can be used as a transflective plate of a liquid crystal display device.
That is, if a PBS array is provided between the liquid crystal layer and the backlight, external light incident from above the upper substrate passes through the liquid crystal layer and changes its polarization state to reach the PBS array. While one linearly polarized light is reflected and returns to the upper substrate side, the other linearly polarized light is transmitted downward, whereby a bright / dark display in the reflection mode can be performed. In addition, one of the light emitted from the backlight is transmitted through the PBS array and contributes to the display, and this linearly polarized light is transmitted through the liquid crystal layer and changes its polarization state to display light and dark in the transmission mode. It can be performed.
According to this liquid crystal display device, there is no conversion from circularly polarized light to linearly polarized light or conversion from linearly polarized light to circularly polarized light when using external light or backlight light for display. And a relatively bright display is possible.
[0006]
However, the principle of a transflective plate using a PBS array having a dielectric multilayer film is based on multiple reflection interference in the dielectric multilayer film, and the optical characteristics (spectral characteristics and polarization characteristics) of the reflector are based on the incidence of light. The liquid crystal display device having the transflective plate has a problem that the display color looks different depending on the viewing angle in the reflection mode display because it has a characteristic that it largely depends on the angle and the observation direction. It was.
[0007]
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a liquid crystal display device that has improved viewing angle characteristics, little coloring, and excellent visibility.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the liquid crystal display device of the present invention includes a liquid crystal layer sandwiched between a first substrate and a second substrate facing each other, and a first polarizing layer on the first substrate side of the liquid crystal layer. And a reflective polarizing layer is provided on the second substrate side of the liquid crystal layer, wherein the reflective polarizing layer has a plurality of dielectrics on a plurality of slopes of ridges having a triangular wave cross section. It has a dielectric laminated film formed by laminating body films, and the dielectric laminated film is formed in different film thicknesses in the ridge line portion of the ridge and the valley line portion of the ridge. Yes.
In other words, the liquid crystal display device of the present invention includes a lower reflective polarizing layer (so-called PBS array type reflective polarizing layer) having a dielectric laminated film formed on the slope of a ridge having a triangular wave cross section as a semi-transmissive reflective layer. It is a transflective liquid crystal display device. And the said dielectric laminated film is formed so that a film thickness may change continuously along the slope of the said protruding item | line. According to this configuration, the reflection characteristics of the dielectric laminated film can be varied to some extent by the change in the film thickness on the inclined surface, so that the phenomenon that the reflected light appears to be colored depending on the viewing angle is alleviated. Thereby, the display angle dependence is small, and a display with little coloring is obtained.
[0009]
In the liquid crystal display device of the present invention, the film thickness of the dielectric laminated film in the ridge line portion of the ridge is 1.1 times or more of the film thickness of the dielectric laminated film in the valley line portion of the ridge or 0.9. It is preferable that the ratio is not more than twice.
By setting the ratio of the film thickness at each part of the dielectric laminated film within the above range, coloring of display light depending on the viewing angle can be reduced and high-quality display can be obtained. When the ratio of the film thickness is less than 1.1 times or more than 0.9 times, the difference in film thickness between the ridge line part and the valley line part of the ridge is too small. Coloring tends to occur.
[0010]
In the liquid crystal display device of the present invention, the film thickness of the dielectric laminated film in the ridge line portion of the ridge is 1.2 times or more the film thickness of the dielectric laminated film in the valley line portion of the ridge, or 0. More preferably, it is 8 times or less.
According to the above configuration, it is possible to more effectively prevent coloring of display light, and it is possible to provide a liquid crystal display device that is particularly excellent in visibility.
[0011]
In the liquid crystal display device of the present invention, the number of layers of the dielectric laminated film is preferably 9 or less.
The number of layers of the dielectric laminated film is more preferably 7 or less.
The dielectric laminated film is preferably made as thin as possible in order to increase the transmittance in a range where the reflection characteristic and polarization characteristic as a PBS array can be obtained, and the dielectric laminated film applied to the liquid crystal display device according to the present invention In the film, the number of layers does not need to be 10 or more.
[0012]
In the liquid crystal display device of the present invention, it is preferable that at least one dielectric film of the dielectric films constituting the dielectric multilayer film has a thickness of 15 nm or less.
According to the above configuration, it is possible to configure a liquid crystal display device that more effectively suppresses coloring of display light and is particularly excellent in viewing angle characteristics and visibility.
[0013]
Next, an electronic apparatus according to the present invention includes the liquid crystal display device according to the present invention described above. According to such a configuration, it is possible to provide an electronic device including a display unit that is less visible and has less coloration and that has less coloration and has excellent visibility.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
(First embodiment)
FIG. 1 is a cross-sectional structure diagram showing a configuration of a liquid crystal display device according to a first embodiment of the present invention. The liquid crystal display device of this embodiment is an example of a passive matrix transflective color liquid crystal display device. In each of the following drawings, the film thicknesses and dimensional ratios of the constituent elements are appropriately changed in order to make the drawings easy to see.
[0015]
In the liquid crystal display device according to the present embodiment, as shown in FIG. 1, a lower substrate 2 and an upper substrate 3 are arranged to face each other, and a liquid crystal layer made of STN (Super Twisted Nematic) liquid crystal is formed in a space between these substrates 2 and 3. 4 has a liquid crystal cell sandwiched therebetween.
A lower reflective polarizing layer 6 described later is formed on the inner surface side of the lower substrate 2 made of a transparent substrate such as glass or resin, and indium tin oxide (hereinafter referred to as ITO) is formed on the lower reflective polarizing layer 6. A stripe-shaped scanning electrode 8 made of a transparent conductive film such as abbreviated) extends in the horizontal direction in the figure, and an alignment film 9 made of polyimide or the like is laminated so as to cover the scanning electrode 8. A lower polarizing plate 20 is provided on the outer surface side of the lower substrate 2. Further, a backlight having a light source, a reflector, a light guide plate, a reflection plate, and the like is provided on the outer surface side of the lower polarizing plate.
[0016]
On the other hand, on the inner surface side of the upper substrate 3 made of a transparent substrate such as glass or resin, color material layers of R (red), G (green), and B (blue) are orthogonal to the scanning electrodes 8 of the lower substrate 2. Extend in a direction perpendicular to the paper surface and are repeatedly arranged in this order to constitute a color filter. Then, a flattening film 12 for flattening unevenness due to the color material layer of the color filter is laminated. A striped signal electrode 14 made of a transparent conductive film such as ITO extends on the planarizing film 12 in a direction perpendicular to the paper surface, and an alignment film 15 made of polyimide or the like is formed on the scanning electrode 14. They are stacked. A front scattering plate 16, a phase difference plate 17, and an upper polarizing plate 13 are provided in this order on the outer surface side of the upper substrate 3.
[0017]
2 is an enlarged partial cross-sectional view of the lower reflective polarizing layer 6 shown in FIG. 1, and FIG. 3 is an enlarged partial cross-section of one of the ridges 42 shown in FIG. FIG.
As shown in FIG. 2, the lower reflective polarizing layer 6 includes a base material layer 44 made of a transparent resin such as acrylic formed on the lower substrate, and a dielectric laminated film 40 in which a plurality of dielectric films are laminated. And a transparent resin layer 45 made of acrylic or the like formed to protect the dielectric laminated film 40 and flatten the upper surface side of the lower reflective polarizing layer 6 in the figure. The base material layer 44 has a plurality of triangular prism-shaped ridges 42 having two inclined surfaces, and the plurality of ridges 42 are formed continuously and periodically to form a triangular wave shape in cross section. .
[0018]
As shown in FIG. 3, the dielectric laminated film 40 is a film in which a dielectric film 41 made of two kinds of materials having different refractive indexes is formed along the slope of the ridge 42. In the case of this embodiment, for example, TiO ₂ Film and SiO ₂ Seven layers are laminated alternately with the film. The film thickness of one dielectric film 41 is about 10 nm to 100 nm, and the total film thickness of the dielectric laminated film is about 300 nm to 1000 nm. The height of the ridge 42 is 0.5 μm to 3 μm. Further, the pitch between the ridges 42 is set to about 1 μm to 6 μm. As the material of the dielectric film 41, the above TiO ₂ , SiO ₂ And Ta ₂ O ₅ Si, etc. can be used.
As shown in FIG. 3, the dielectric laminated film 40 according to the present embodiment is formed by gradually changing the film thickness along the slope of the ridge 42, and the valley line portion of the ridge 42. The film thickness a of the dielectric multilayer film 40 in FIG. 5 is different from the film thickness b of the dielectric multilayer film 40 in the ridge line portion of the ridge 42. It is not necessary for the rate of change in film thickness at this time to be constant along the slope of the ridge 42. With this configuration, the reflection characteristics of the dielectric multilayer film 40 can be varied to some extent, and the spectral characteristics and polarization characteristics of the dielectric multilayer film that have been sensitively changed according to the viewing angle can be compensated for each other. it can. As a result, the liquid crystal display device according to the present invention can obtain reflection characteristics and transmission characteristics with less tint.
[0019]
In the case where the lower reflective polarizing layer 6 having the above configuration is arranged so that the ridges 42 extend perpendicular to the paper surface as shown in FIG. It has a function of reflecting a part of the light, transmitting a part of the light, and separating the polarized light. Specifically, as shown in FIG. 2, the reflected light Lr becomes a linearly polarized light perpendicular to the paper surface. Lt is linearly polarized light parallel to the paper surface.
[0020]
In the liquid crystal display device of this embodiment, the ratio a / b between the film thickness a in the valley line portion of the ridge 42 and the film thickness b in the ridge line portion is 1.1 or more or 0.9 or less. It is preferable to adjust the film thickness of each part of the dielectric laminated film 40, and more preferably, the ratio a / b is 1.2 or more, or 0.8 or less. That is, the maximum displacement width of the film thickness in the plane of the dielectric laminated film 40 is preferably 10% or more, and more preferably 20% or more.
As the difference in the film thickness of the dielectric multilayer film 40 increases, the variation in the reflection characteristics of the dielectric multilayer film 40 can be increased, and the display coloring and viewing angle dependency can be reduced more effectively. Since manufacturing becomes difficult if the dielectric film 41 is extremely thick (or thin) depending on the part, the displacement width of the film thickness is preferably 50% or less.
[0021]
As described above, according to the liquid crystal display device of the present embodiment having the above-described configuration, the dielectric laminated film 40 constituting the lower reflective polarizing layer 6 is formed by partially varying the film thickness in the plane. Since the reflection characteristics of the dielectric laminated film 40 have a certain degree of variation, it is possible to prevent the display from being tinted or from being colored depending on the viewing angle, thereby obtaining a display with excellent visibility. be able to.
[0022]
In this embodiment mode, the configuration in which the present invention is applied to a transflective passive matrix liquid crystal display device has been described. However, the present invention is not limited to a reflective liquid crystal display device or an active matrix liquid crystal display device. Of course, the present invention can be applied without any problem.
[0023]
Hereinafter, the operation principle of the liquid crystal display device of the present embodiment shown in FIG. 1 will be described with reference to FIG.
The operation principle of the liquid crystal display device having this configuration will be described below. 4A and 4B are explanatory diagrams for explaining the operation principle when the present invention is applied to a transflective liquid crystal display device. FIG. 4A shows light in a transmission mode and FIG. 4B shows light in a reflection mode. Shows the route. In these drawings, only the components necessary for the description are shown among the components of the liquid crystal display device of the present invention, and an upper polarizing plate 54 and a lower reflective polarizing layer 51 are provided above and below the liquid crystal 53. The lower substrate 50 is disposed outside the lower reflective polarizing layer 51, and the lower polarizing layer 55 is formed on the outer surface side of the lower substrate 50. An illumination device 58 is provided on the outer side (lower surface side in the drawing) of the lower polarizing layer 55, and a reflection plate 59 is provided on the outer surface side of the illumination device 58.
[0024]
The upper polarizing plate 54 has a transmission axis perpendicular to the paper surface, and the lower polarizing layer 55 has a transmission axis parallel to the paper surface. The lower reflective polarizing layer 51 is a transflective reflective polarizing layer, and has a transmission axis perpendicular to the paper surface and a reflection axis perpendicular to the transmission axis. The polarized light parallel to the transmission axis transmits most of it and reflects the remaining components, but the polarized light parallel to the reflection axis reflects most of the light and transmits some of the light. It has become. That is, the lower reflective polarizing layer 51 is a semi-transmissive reflective type for polarized light parallel to the reflection axis. The lower reflective polarizing layer 51 has the same configuration as the reflective polarizing layer 44 shown in FIG. 4, and is arranged so that the transmission axis is perpendicular to the paper surface of FIG. That is, the grooves of the reflective polarizing layer 44 shown in FIG. 4 are arranged so as to be parallel to the paper surface of FIG.
[0025]
Hereinafter, a case where display is performed in the transmission mode illustrated in FIG.
In the liquid crystal display device of the present invention, the transmission mode display is performed using the light emitted from the illumination device 58. The light emitted from the illumination device 58 is converted into polarized light parallel to the paper surface by the lower polarizing layer 55 having a transmission axis parallel to the paper surface, and then passes through the lower substrate 50 and enters the lower reflective polarizing layer 51. The lower reflective polarizing layer 51 has a transmission axis perpendicular to the paper surface as described above, and a part of the light polarized parallel to the paper surface by the lower polarizing layer 55 is reflected to the illumination device 58 side. The reflected light 61 is returned, and part of the reflected light 61 is transmitted and is transmitted light 60 that enters the liquid crystal 53.
[0026]
Next, the transmitted light 60 incident on the liquid crystal 53 reaches the upper polarizing plate 54 with almost no action of the liquid crystal 53 when a voltage is applied to the liquid crystal 53 (on state), and is perpendicular to the paper surface. Is absorbed by the upper polarizing plate 54 having a transparent axis, and the pixel is darkly displayed. On the other hand, if no voltage is applied to the liquid crystal 53 (off state), the transmitted light 60 incident on the liquid crystal 53 is converted into polarized light perpendicular to the paper surface by the optical rotation of the liquid crystal 53, and is transmitted to the upper polarizing plate 54. To reach. The light, which is polarized light parallel to the transmission axis of the upper polarizing plate 54, passes through the upper polarizing plate 54, so that the pixels are brightly displayed.
[0027]
Here, when attention is focused on the reflected light 60 reflected on the back surface side (lower substrate 50 side) of the lower reflective polarizing layer 51, the reflected light 60 passes through the lower substrate 50 and the lower polarizing layer 55 to the illumination device 58. Then, the light is reflected by the reflection plate 59 provided on the outer surface side of the illumination device 58 and is reused as the light toward the lower polarizing layer 55 again. Then, this light reaches the lower reflective polarizing layer 51 again, part of it is transmitted and enters the liquid crystal 53, and part of it is reflected and returned to the illumination device 58 side. Thus, the light reflected by the lower reflective polarizing layer 51 passes through the lower reflective polarizing layer 51 while being repeatedly reflected between the lower reflective polarizing layer 51 and the reflection plate 59, and is used as light contributing to display. . Therefore, in the liquid crystal display device of the present invention, light transmitted through the lower polarizing layer 55 among the light emitted from the illumination device 58 can be utilized to the maximum, and a bright display can be obtained.
[0028]
Next, a case where display is performed in the reflection mode illustrated in FIG.
As shown in FIG. 4B, light incident from above the upper polarizing plate 54 is first converted into polarized light perpendicular to the paper surface by the upper polarizing plate 54 having a transmission axis perpendicular to the paper surface, and enters the liquid crystal 53. To do. Next, if the liquid crystal is in an ON state, the incident light reaches the lower reflective polarizing layer 51 with almost no action by the liquid crystal 53. Since the lower reflective polarizing layer 51 has a transmission axis perpendicular to the paper surface and a reflective axis parallel to the paper surface, the light reaching the lower reflective polarizing layer 51 is transmitted through the lower reflective polarizing layer 51. Thereafter, the light passes through the lower substrate 50 and is absorbed by the lower polarizing layer 55 having a transmission axis parallel to the paper surface, and the pixels are darkly displayed.
[0029]
On the other hand, if the liquid crystal 53 is in the OFF state, the light incident on the liquid crystal 53 is converted into polarized light parallel to the paper surface by the optical rotation of the liquid crystal 53 and reaches the lower reflective polarizing layer 51. A part of the light is reflected by the lower reflective polarizing layer 51 having a reflection axis parallel to the paper surface to be reflected light 63, and part of the light is transmitted to be transmitted light 62. The reflected light 63 incident on the liquid crystal 53 again is converted into polarized light perpendicular to the paper surface again by the optical rotation of the liquid crystal 53, passes through the upper polarizing plate 54, and the pixels are brightly displayed. The transmitted light 62 transmitted through the lower reflective polarizing layer 51 is transmitted through the lower substrate 50 and the lower polarizing layer 55 and is emitted to the illumination device 58. Since the illuminating device 58 is provided with the reflecting plate 59, a part of the transmitted light 62 is reflected by the reflecting plate 59 and returns to the lower substrate 50 side. Since the selected pixel becomes brighter, the light transmitted through the lower reflective polarizing layer 51 does not adversely affect the display.
[0030]
(Second Embodiment)
In the first embodiment, the configuration in which the lower reflective polarizing layer 6 is provided on the entire surface in the display region has been described. However, in the liquid crystal display device according to the present invention, the lower reflective polarizing layer is the lower substrate. A configuration in which a lower polarizing layer is provided on a lower surface of the lower reflective polarizing layer can also be applied. This configuration will be described below as a second embodiment of the present invention with reference to FIG.
The liquid crystal display device shown in FIG. 5 is different from the transflective liquid crystal display device shown in FIG. 1 in that a lower reflective polarizing layer provided with an opening 10 for transmitting light emitted from the backlight 5. The other configuration is the same as that of the liquid crystal display device shown in FIG. Therefore, among the components shown in FIG. 5, the same components as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.
[0031]
The lower reflective polarizing layer 36 provided in the liquid crystal display device of the present embodiment shown in FIG. 5 is the same as the lower reflective polarizing layer 6 shown in FIG. 1 except that a plurality of openings 10 corresponding to the respective dots are formed. It has the same structure, and has a structure in which the dielectric laminated film having the structure shown in FIGS. 2 and 3 is formed along the slope of the ridge.
Therefore, also in the lower reflective polarizing layer 36 according to this embodiment, the film thickness of the dielectric laminated film 40 is formed so as to be different from each other at the ridge line portion and the valley line portion of the ridge 42. A certain degree of variation is imparted to the reflection characteristics of the layer 36, so that it is possible to prevent the display from being colored or the display from being colored depending on the viewing angle.
[0032]
Also with the liquid crystal display device of the present embodiment, display in which the transmission mode and the reflection mode are switched can be performed as in the liquid crystal display device of the first embodiment shown in FIG. Hereinafter, the operation principle of the liquid crystal display device of this embodiment shown in FIG. 5 will be described with reference to FIG.
FIG. 6 is an explanatory diagram for explaining the operation principle of the transflective liquid crystal display device according to the present invention. The liquid crystal display device shown in this figure has an upper polarizing plate 54 and a lower reflective material above and below the liquid crystal 53. A polarizing layer 51 is provided, and a lower substrate 50 and a lower polarizing layer 55 are disposed below the lower reflective polarizing layer 51, and an illumination device 58 and a reflective plate 59 are provided on the outer surface side of the lower polarizing layer 55. . In the liquid surface display device of this configuration, an opening 57 for transmitting the light emitted from the illumination device 58 is provided in the lower reflective polarizing layer 51, and the others are as shown in FIG. It is the same composition. 6 that are denoted by the same reference numerals as those in FIG. 4 are the same as those in FIG. 4, and detailed descriptions thereof are omitted.
[0033]
When performing transmission mode display in the liquid crystal display device shown in FIG. 6, as shown in FIG. 6A, the light emitted from the illumination device 58 is converted into polarized light parallel to the paper surface by the lower polarizing layer 55. The light is converted and transmitted through the lower substrate 50, and then a part of the light passes through the opening 57 and enters the liquid crystal 53 to be used for display. If the liquid crystal 53 is in an on state, the light incident on the liquid crystal 53 reaches the upper polarizing plate 54 with almost no action by the liquid crystal 53, and is absorbed by the upper polarizing plate 54 having a transmission axis perpendicular to the paper surface. Pixels are darkly displayed. On the other hand, if the liquid crystal 53 is in an off state, the light is converted from polarized light parallel to the paper surface to polarized light perpendicular to the paper surface by the optical rotation of the liquid crystal and transmitted through the upper polarizing plate 54 so that the pixels are brightly displayed. .
[0034]
Further, the light that does not enter the opening 57 of the lower reflective polarizing layer 51 and is reflected on the lower surface side of the lower reflective polarizing layer 51 is returned to the illumination device 58 side, and is reflected by the reflector 59 on the outer surface side of the illumination device 58. The light is reflected and becomes incident on the lower reflective polarizing layer 51 again. Thus, while reflection is repeated between the lower reflective polarizing layer 51 and the reflection plate 59, the light enters the opening 57 and is used for display. Therefore, according to this configuration, a bright display can be obtained in the transmission mode, and a liquid crystal display device excellent in visibility can be provided.
[0035]
When the reflective mode display is performed in the liquid crystal display device shown in FIG. 6, the external light incident from above the upper polarizing plate 54 is perpendicular to the paper surface by the upper polarizing plate 54, as shown in FIG. It is converted into polarized light and enters the liquid crystal 53. Here, if the liquid crystal 53 is in an on state, the incident light reaches the lower reflective polarizing layer 51 without being affected by the liquid crystal 53 and is transmitted through the lower reflective polarizing layer 51 having a transmission axis perpendicular to the paper surface. And reaches the lower polarizing layer 55. Then, the light is absorbed by the lower polarizing layer 55 having a transmission axis parallel to the paper surface. In this way, the pixels are darkly displayed.
On the other hand, when the liquid crystal 53 is in the off state, the incident light is converted into polarized light parallel to the paper surface by the optical rotation of the liquid crystal 53 and reaches the lower reflective polarizing layer 51, and the transmission axis perpendicular to the paper surface (on the paper surface). The light is reflected by the lower reflective polarizing layer 51 having a parallel reflection axis) and is directed to the liquid crystal 53 side, and is converted again into polarized light perpendicular to the paper surface by the optical rotation of the liquid crystal 53, and has a transmission axis perpendicular to the paper surface. The light passes through the upper polarizing plate 54 and is emitted upward. In this way, the pixels are brightly displayed.
[0036]
(Electronics)
FIG. 7 is a perspective configuration diagram of a mobile phone which is an example of an electronic apparatus provided with a liquid crystal display device according to the present invention in a display unit. The mobile phone 1300 includes a liquid crystal display device of the present invention in a small size display unit. 1301, and includes a plurality of operation buttons 1302, a mouthpiece 1303, and a mouthpiece 1304.
The liquid crystal display device of the above embodiment is not limited to the mobile phone, but is an electronic book, a personal computer, a digital still camera, a liquid crystal television, a viewfinder type or a monitor direct view type video tape recorder, a car navigation device, a pager, and an electronic notebook. It can be suitably used as image display means for calculators, word processors, workstations, videophones, POS terminals, devices equipped with touch panels, etc., and any electronic device can provide high-quality color display. .
[0037]
【Example】
(Example 1)
In this example, the configuration shown in FIG. 1 is used as a basic configuration, and the film thicknesses a and b of the dielectric laminated film 40 shown in FIG. 3 are variously changed to provide five types (samples 1 to 5 shown in Table 2). A liquid crystal display device was produced and its visibility was evaluated.
[0038]
In producing each sample of this example, the lower reflective polarizing layer 6 was produced by the following steps.
First, a prism array having an inclination angle of 45 ° to 55 ° (an angle formed between the main surface of the lower substrate 2 and the inclined surface of the ridge 42) was formed on the lower substrate 2 by a laminating method. Next, a dielectric laminated film 40 was formed by laminating a plurality of dielectric films 41 by RF ion plating (may be sputtering or vacuum deposition). At this time, the dielectric laminated film 40 was formed so that the film thickness was different between the ridge line portion and the valley line portion of the ridge 42 of the prism array by adjusting the production conditions such as the substrate temperature and the atmospheric gas flow rate.
In this example, the basic configuration of the dielectric laminated film 40 is the film configuration and the film thickness ratio shown in Table 1, and the film thickness a in the valley line portion of the ridge 42 and the film thickness b in the ridge line portion are represented. The combinations shown in 2 were used.
Next, the dielectric laminated film 40 was overcoated with an acrylic resin to form a resin layer 45 to obtain a lower reflective polarizing layer 6 having a flattened surface.
And the liquid crystal display device of the samples 1-5 of the structure shown in FIG. 1 was produced by using the lower board | substrate 2 in which the lower reflective polarizing layer 6 was formed by the said process for the manufacturing process of a well-known liquid crystal panel.
[0039]
Next, the liquid crystal display devices of Samples 1 to 5 obtained by the above process were operated, and the white display in the reflection mode was visually observed to evaluate the coloring and viewing angle characteristics. The results are also shown in Table 2.
As shown in Table 2, the ratio a / b between the film thickness a of the dielectric laminated film 40 in the valley line portion of the ridge 42 and the film thickness b in the ridge line portion is 1.1 or more or 0.9 or less. In the liquid crystal display devices of Samples 1, 4 and 5 in the range, it was confirmed that good reflection display can be obtained with little coloration and small viewing angle dependency. In particular, the liquid crystal display devices of Samples 1 and 5 in which the film thickness ratio a / b was 1.2 or more or 0.8 or less were more excellent in white display color and viewing angle dependency.
On the other hand, in the liquid crystal display devices of Samples 2 and 3 in which the ratio a / b is in the range of more than 0.9 and less than 1.1, the white display appears colored, and the coloration depends on the viewing angle. Tended to be.
[0040]
[Table 1]

[0041]
[Table 2]

[0042]
(Example 2)
Next, in the liquid crystal display device shown in FIG. 1, samples in which the film thicknesses of the dielectric films 41 constituting the dielectric laminated film 40 of the lower reflective polarizing layer 6 are variously manufactured are prepared, and the reflective display is visually recognized The sex was verified. The liquid crystal display device manufactured in this example has the basic configuration shown in FIG. 1 as in Example 1, and the layer configuration of the dielectric laminated film 40 is the configuration shown in Table 3. Further, in each sample, the film thickness a of the dielectric laminated film 40 in the valley line portion of the ridge 42 and the film thickness b in the ridge line portion were combinations shown in Table 4. Note that the manufacturing method of each sample is the same as in Example 1.
[0043]
Next, the sample liquid crystal display devices having the layer configurations 1 to 3 obtained by the above steps were operated, and the white display in the reflection mode was visually observed to evaluate the coloring and viewing angle characteristics. The results are also shown in Table 4.
As shown in Table 4, in the sample of this example, the ratio a / b between the film thickness a of the dielectric laminated film 40 in the valley line portion of the ridge 42 and the film thickness b in the ridge line portion is 0. .8 or less, both of which are small in color and have a small viewing angle dependency, and a good reflective display was obtained. Thus, a very good display with almost no viewing angle dependency was realized.
The sample of this layer thickness configuration 3 is one in which the second layer of the dielectric laminated film 40 is 10.1 nm, but is similarly compared to the sample of the layer configuration 2 in which the second layer is thinned to 21.6 nm. Therefore, if at least one of the dielectric films 41 constituting the dielectric laminated film has a film thickness of 15 nm or less, the coloration and viewing angle characteristics of the display are remarkably improved. It is suggested that it can be done.
[0044]
[Table 3]

[0045]
[Table 4]

[Brief description of the drawings]
FIG. 1 is a diagram showing a partial cross-sectional structure of a transflective liquid crystal display device according to a first embodiment of the present invention.
FIG. 2 is an enlarged partial cross-sectional view showing a lower reflective polarizing layer shown in FIG.
FIG. 3 is an enlarged partial cross-sectional view showing one of the ridges shown in FIG. 2;
4 is an explanatory diagram for explaining the operation of the liquid crystal display device shown in FIG. 1; FIG.
FIG. 5 is a diagram showing a partial cross-sectional structure of a transflective liquid crystal display device according to a second embodiment of the present invention.
6 is an explanatory diagram for explaining the operation of the liquid crystal display device shown in FIG. 5; FIG.
FIG. 7 is a perspective configuration diagram illustrating an example of an electronic apparatus according to the invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Liquid crystal display device, 2 Lower substrate, 3 Upper substrate, 4 Liquid crystal layer, 5 Backlight, 6,36 Lower reflective polarizing layer, 11 Color filter, 13 Upper polarizing plate (upper polarizing layer), 16 Forward scattering plate, 20 Lower Polarizing plate (lower polarizing layer)

Claims (7)

A liquid crystal display device in which a liquid crystal layer is sandwiched between a first substrate and a second substrate, and the first substrate side is a viewing side,
A first polarizing layer provided on the viewing side of the first substrate;
A reflective polarizing layer provided between the liquid crystal layer and the second substrate,
The reflective polarizing layer includes a plurality of ridges having a triangular wave cross section ,
Anda dielectric multilayer film in which a plurality of dielectric films are stacked on the inclined surface of the convex,
The total film thickness of the dielectric laminated film in the ridge line portion of the ridge is 1.1 times or more or 0.9 times or less than the total film thickness of the dielectric laminated film in the valley line portion of the ridge. A characteristic liquid crystal display device. The film thickness of the dielectric laminated film in the ridge line portion of the ridge is 1.2 times or more, or 0.8 times or less of the film thickness of the dielectric laminated film in the valley line portion of the ridge. The liquid crystal display device according to claim 1 . The liquid crystal display device according to claim 1 or 2 wherein wherein the number of layers of the dielectric multilayer film is less than 9 layers. The liquid crystal display device according to claim 3 , wherein the number of layers of the dielectric laminated film is 7 or less. Wherein of the dielectric film constituting the dielectric multilayer film, a liquid crystal display according to any one of claims 1 to 4, characterized in that the thickness of the dielectric film at least one layer is a 15nm or less apparatus. The liquid crystal display device according to claim 1, wherein the reflective polarizing layer has an opening at a position overlapping with a pixel. An electronic apparatus comprising the liquid crystal display device according to any one of claims 1 to 6.

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