JP3693055B2 - Liquid crystal display device and electronic device - Google Patents

Description

【００４８】
なお、カラーフィルタの種類については、表２に示すように比較例１と、実施例１〜７については反射率Ｙ及び色度ｘ，ｙの同じものを用い、比較例２についてはこれら比較例１及び実施例１〜７とは反射率Ｙ及び色度ｘ，ｙの異なるものを用いた。
【００４９】
【表２】

【００５０】
そして、これら比較例１〜２及び実施例１〜７の液晶表示装置について、反射表示時の反射率及び色域面積を測定し、また透過表示時についても透過率及び色域面積を測定した。ここで、色域面積とはＣＩＥ色度図上で赤・緑・青の表示色を（ｘ，ｙ）座標で表したときの各点を結ぶ三角形の面積である。
【００５１】
表１から分かるように、比較例２の液晶表示装置は緑色のドットにおいて表２に示すような緑のカラーフィルタに色純度の低いカラーフィルタを用いて反射および透過の白表示色の着色を抑えたため、透過表示時の色域面積が小さくなっている。そこで、表２のようにカラーフィルタの種類を比較例１のように変更した場合には、透過表示時の色域面積は大きくなったものの、透過表示時及び反射表示時の白表示が黄緑色に着色した。そこで、実施例１のように緑色のドットにおいて透過表示領域の面積比率を減らすことにより、透過表示時の緑の発色を良好に保ったまま白表示の黄緑色の着色を抑えることができた。さらに、緑色のドット面積比率を小さくすることにより、緑色のドットについて反射表示領域の面積比率を小さくしたため、反射表示時の白表示における黄緑色の着色を抑えることもできた。
【００５２】
さらに実施例２〜４の液晶表示装置では、緑色のドットの反射表示領域にカラーフィルタの無い領域を形成した。すなわち、緑色のドットの反射表示領域にカラーフィルタの非着色領域を形成したのである。実施例２では、反射表示時の白表示をやや犠牲にし、実施例３では、透過表示時の白表示をやや犠牲にしているが、実施例４では反射表示領域においてカラーフィルタの無い部分を緑色のドット以外に、赤色、青色のドットに対しても設けることにより、実施例２や実施例３のような白表示における着色を改善している。なお、実施例４の場合、反射表示時の色域面積は犠牲にしているが、透過表示では色域面積が画質的に優先されるのに対し、反射表示においては色域面積よりも明るさが優先される。
【００５３】
なお、実施例５の液晶表示装置については、緑色のドットの面積比率と、緑色のドットにおいてカラーフィルタと重畳する反射表示領域の面積比率（緑の反射部カラーフィルタあり面積比率）とを非常に小さくしたため、白表示における黄緑色の着色を抑えることはできたが、反射表示時の色域面積が非常に小さいものとなった。また、実施例６の液晶表示装置では、緑色のドットについて透過表示領域の面積比率を非常に小さくしたために、透過表示時における白表示の着色を抑えることはできたが、該透過表示の色域面積が非常に小さいものとなった。さらに、実施例７の液晶表示装置では、緑色のドットにおいてカラーフィルタと重畳する反射表示領域の面積比率を非常に小さくしたため、反射表示時における白表示の着色を抑えることはできたが、該反射表示の色域面積が非常に小さいものとなった。
【００５４】
したがって、白表示の着色を抑える上では、緑色のドットについて、ドット面積ＳＧ、透過表示領域面積ＴＧ、反射表示領域とカラーフィルタとの重畳面積ＲＧを、他の色のドットよりも相対的に小さくすることが好ましいが、色域面積を所定値（例えば１．１×１０^−２）以上に確保するためには、透過表示領域面積ＴＧについては０．２０＜（ＴＧ／（ＴＲ＋ＴＧ＋ＴＢ））＜０．３３、重畳面積ＲＧについては０．２６＜（ＲＧ／（ＲＲ＋ＲＧ＋ＲＢ））＜０．３３、ドット面積ＳＧについては０．２６＜（ＳＧ／（ＳＲ＋ＳＧ＋ＳＢ））＜０．３３を満たすことが好ましいことが分かる。しかし例えば、反射率が２２％以上であれば反射の色域面積を０．９×１０^−２以上でも反射の見栄え上良いものであるので、重畳面積ＲＧについては０．２０＜（ＲＧ／（ＲＲ＋ＲＧ＋ＲＢ））＜０．３３を満たせば良い。
【図面の簡単な説明】
【図１】 第１の実施の形態の液晶表示装置について概略構成を示す平面図（ａ）及び断面図（ｂ）。
【図２】 反射膜の一例を模式的に示す斜視図。
【図３】 図２の反射膜の平面図。
【図４】 図２の反射膜の作用を示す説明図。
【図５】 第２の実施の形態の液晶表示装置について概略構成を示す平面図（ａ）及び断面図（ｂ）。
【図６】 第３の実施の形態の液晶表示装置について概略構成を示す平面図（ａ）及び断面図（ｂ）。
【図７】 本発明の電子機器の一例を示す斜視図。
【符号の説明】
１…液晶表示装置、２…液晶セル、３…バックライト（照明手段）、４…下基板、５…上基板、７…液晶層、８…反射膜、１３…カラーフィルタ、１３Ｒ，１３Ｇ，１３Ｂ…色素層、２８Ｒ，２８Ｇ，２８Ｂ…ドット、２９…画素、３１Ｒ，３１Ｇ，３１Ｂ…非着色領域[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a liquid crystal display device and an electronic device, and more particularly to a transflective liquid crystal display device capable of displaying a sufficiently bright display with little color not only in a reflection mode but also in a transmission mode.
[0002]
[Prior art]
A transflective liquid crystal display device having both a reflective mode and a transmissive mode is known. In particular, as a transflective color liquid crystal display device, a color filter is provided on either the upper substrate or the lower substrate. Things have been proposed. In the case of this type of transflective color liquid crystal display device, in the reflection mode, external light incident from the upper substrate side passes through the color filter, is reflected by the reflective layer, and then passes through the color filter again. ing. On the other hand, in the transmission mode, illumination light incident from the lower substrate side by illumination means such as a backlight is transmitted through the color filter. In a normal configuration, display is performed using the same color filter in both the reflection mode and the transmission mode.
[0003]
In such a transflective color liquid crystal display device, as described above, the incident light passes through the color filter twice in the reflection mode and once in the transmission mode, so that a color display can be obtained. ing. For this reason, there is a difference in color density between the reflection mode and the transmission mode, and in order to correct this, for example, in Patent Document 1, the area of the pixel portion is made different in correspondence with each color of the color filter in the region where the reflection display is performed. Yes.
[0004]
[Patent Document 1]
JP 2002-182191 A
[0005]
[Problems to be solved by the invention]
However, although the configuration as in Patent Document 1 can correct the color of the reflective region, the transmissive region is not considered at all. That is, even if color correction is performed in the reflective area and the brightness of the display is ensured, on the other hand, a color density difference may occur in the transmissive area. Therefore, a technique capable of performing a preferable color display in both areas is desired. It is rare.
[0006]
The present invention has been made to solve the above-described problems, and in a transflective color liquid crystal display device, it is less colored and bright and particularly visible in white display both in the reflection mode and in the transmission mode. An object of the present invention is to provide a liquid crystal display device capable of obtaining a high display. Moreover, an object of this invention is to provide the electronic device provided with the said liquid crystal display device which has the outstanding visibility.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, a liquid crystal display device according to the present invention includes a pair of substrates each composed of an upper substrate and a lower substrate disposed to face each other, a liquid crystal layer sandwiched between the pair of substrates, and the lower substrate. A reflective layer that reflects incident light from the upper substrate side, and a red, green, and blue dye layer that corresponds to each dot that is provided above the reflective layer and that constitutes the display area. Are arranged on the outer surface side of the lower substrate, and a reflective area where the reflective layer exists for each dot and a transmissive area where the reflective layer does not exist. In the transflective liquid crystal display device to perform, the area of the transmissive region in one dot is minimized in the dot corresponding to the green pigment layer among the red, green, and blue pigment layers, Colored region of the color filter and the reflection The area that overlaps the area on the plane is the minimum for the dots corresponding to the green dye layer among the red, green, and blue dye layers, and the area of one dot is each of the red, green, and blue dye layers Among the dots corresponding to the green pigment layer.
[0008]
Conventionally, in a transflective color liquid crystal display device as described in Patent Document 1, if the short wavelength side is made relatively high in black display in order to increase the contrast, yellow light can be displayed in white display during both transmission and reflection. Easy to color green. As a countermeasure, a method of thinning the green color filter is conceivable, but in that case, green coloring may be deteriorated.
Therefore, in the present invention, a method for improving the color development of green is proposed. First, as a first requirement, the area of the transmission region in one dot is set to green among the red, green, and blue dye layers. Minimized for dots corresponding to the dye layer. As a result, it is possible to prevent or suppress the occurrence of yellowish green coloring in the transmissive region during white display without degrading the green coloration during green display.
As a second requirement, the area where the colored region and the reflective region of the color filter overlap on the plane is minimized in the dots corresponding to the green pigment layer among the red, green, and blue pigment layers. As a result, it is possible to prevent or suppress the occurrence of yellowish green coloring without deteriorating the green coloration in the reflective region during white display.
Thus, in the present invention, for the dot corresponding to the green pigment layer, the area of the transmissive region and the area of the reflective region that overlaps with the colored region of the color filter are reduced. If the area is the same for each color, the dot corresponding to the green pigment layer has a large area of the reflection area without color (that is, the area of the reflection area that does not overlap with the colored area). The green color of will become worse. Therefore, in the present invention, as a third requirement, the area of one dot is minimized in the dots corresponding to the green pigment layer among the red, green, and blue pigment layers. As a result, the area of the non-colored reflective region can be made relatively small. As a result, there is little difference in color shade between the reflective display and the transmissive display, and there is little coloring (that is, yellow-green coloring in white display). Display) can be performed.
Since green light has a much higher visibility for human eyes than red light and blue light, the dot area corresponding to the green pigment layer may be set to a minimum as in the present invention. The color reproducibility and brightness when viewed as a whole can be sufficiently secured.
[0009]
In the liquid crystal display device of the present invention, it is desirable that the non-colored region of the color filter is included in at least the dot reflection region corresponding to the green pigment layer. That is, when a region (non-colored region) in which the color filter dye layer does not exist in the reflective region, a part of the light incident from the upper substrate side in the reflective region is transmitted through the non-colored region. The light obtained by passing through the color filter twice in the reflection area is a combination of uncolored light that passes through the non-colored area and colored light that passes through the area where the dye layer is present (colored area). It becomes. On the other hand, all the light emitted from the illumination means and transmitted through the transmission region is transmitted through the colored region, and all the light obtained by passing through the color filter once in the transmission mode is colored light. In this way, the color density difference between the light obtained by passing through the color filter twice in the reflection region and the light obtained by passing through the color filter once in the transmission region can be reduced. It is possible to optimize the dye layer of the filter, and in particular, since the non-colored area is formed in the reflective area that transmits the color filter twice, the display brightness is higher than when the non-colored area is formed in the transmissive area. It is possible to relatively increase the image quality, and it is possible to obtain a bright and highly visible display with good coloring in both the reflection mode and the transmission mode. Since green light has a much higher visibility for human eyes than red light and blue light, as in the present invention, the area of the non-colored region is reduced in dots corresponding to the green pigment layer. By setting the area larger than the area of the non-colored region in the dots corresponding to the red and blue pigment layers, the reflectance and color reproducibility when viewed as the entire reflected light can be improved.
[0010]
Specifically, 0.20 <(TG / (TR + TG + TB)) <0, where TR, TG, and TB are the areas of transmission regions in one dot corresponding to the red, green, and blue dye layers. .33 is preferably satisfied. That is, even when the transmission region area TG of the dot corresponding to the green pigment layer is minimized in each pigment, it is desirable to ensure that the ratio is more than 20%, and within the pixel (region composed of dots of each color) If the ratio of the transmissive region area of the dots corresponding to the green pigment layer is less than 20% in the total transmissive region area, green coloration in transmissive display may be deteriorated.
[0011]
Further, when the area where the colored region and the reflective region of the color filter overlap on the plane corresponding to each of the red, green, and blue pigment layers is RR, RG, RB, 0.26 <(RG / (RR + RG + RB) ) <0.33 is preferably satisfied. That is, even when the area RG in which the color filter and the reflection region overlap on the plane in the dot corresponding to the green pigment layer is minimized in each pigment, it is desirable to secure a ratio of more than 26%. If it is less than 1, the green coloration in the reflective display may deteriorate.
[0012]
Furthermore, when the area of one dot corresponding to each of the red, green, and blue pigment layers is SR, SG, SB, it is preferable that 0.26 <(SG / (SR + SG + SB)) <0.33 is satisfied. . That is, even when the area SG of the dots corresponding to the green pigment layer is minimized in each pigment, it is desirable to ensure that the ratio is more than 26%. When the ratio is below 26%, both the reflective display and the transmissive display are green. Color development may worsen.
[0013]
In the liquid crystal display device of the present invention, the reflective layer can be formed of a metal reflective film. In this case, the reflective layer can be formed at low cost. On the other hand, a reflective polarizing layer in which fine slits are formed in a metal film can also be applied as the reflective layer. As the reflective polarizing layer, it is possible to adopt a layer composed of a grating in which metal films are alternately arranged in a stripe pattern with a period shorter than the wavelength of light. In this case, the grating is transmitted in a direction perpendicular to the extending direction of the stripe. It can have an axis.
[0014]
Next, an electronic apparatus according to the present invention includes the liquid crystal display device according to the present invention. According to this configuration, it is possible to provide an electronic apparatus including a liquid crystal display unit that has good color development in both the reflection mode and the transmission mode, and that is excellent in visibility with little coloration particularly in white display.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
The liquid crystal display device of this embodiment is an example of a passive matrix transflective color liquid crystal display device.
FIG. 1 is a plan view (b) and a cross-sectional view (b) showing a schematic configuration of the liquid crystal display device of the present embodiment, and is a schematic diagram showing the configuration of one pixel in particular. In the following drawings, the film thicknesses and dimensional ratios of the respective components are appropriately changed in order to make the drawings easy to see.
[0016]
As shown in FIG. 1, the liquid crystal display device 1 of the present embodiment includes a liquid crystal cell 2 and a backlight 3 (illuminating means). In the liquid crystal cell 2, a lower substrate 4 and an upper substrate 5 are arranged to face each other via a sealing material (not shown), and STN (Super Twisted Nematic) is provided in a space surrounded by the upper substrate 5, the lower substrate 4, and the sealing material. A liquid crystal layer 7 made of liquid crystal or the like is enclosed, and a backlight 3 is disposed on the rear side of the liquid crystal cell 2 (outer side of the lower substrate).
[0017]
On the inner surface side of the lower substrate 4 made of a light-transmitting material such as glass or plastic, a reflective film 8 made of a metal film having a high light reflectance such as aluminum or an alloy thereof, silver or an alloy thereof is formed in a predetermined pattern. ing. A region where the reflective film 8 is formed is a reflective region, and a region where the reflective film 8 is not formed, that is, an opening region of the reflective film 8 is a transmissive region.
[0018]
A color filter 13 is formed on the inner surface side of the reflective film 8. The color filter 13 includes a light shielding portion 14 (black) that partitions the red (R), green (G), and blue (B) dye layers 13R, 13G, and 13B and the different color layers 13R, 13G, and 13B. In particular, a light shielding portion 14 is formed corresponding to a region where the reflective film 8 is formed. The light shielding portion 14 is made of, for example, resin black or a metal such as chrome having a relatively low reflectivity, and on the color filter 13, the step between the dye layers 13R, 13G, and 13B is flattened and at the same time each dye. An overcoat film 16 for protecting the surfaces of the layers 13R, 13G, and 13B is formed. The overcoat film 16 may be a resin film such as acrylic or polyimide, or may be an inorganic film such as a silicon oxide film.
[0019]
Further, on the overcoat film 16, a stripe-shaped scanning electrode 17 made of indium tin oxide (hereinafter abbreviated as ITO) or the like is formed so as to extend in a direction parallel to the paper surface. An alignment film 18 made of polyimide or the like whose surface is rubbed is formed thereon.
[0020]
On the other hand, on the inner surface side of the upper substrate 5 made of a translucent material such as glass or plastic, a striped signal electrode 9 made of ITO or the like is formed so as to extend in a direction perpendicular to the paper surface. For example, an alignment film 11 made of polyimide or the like whose surface is rubbed is formed.
[0021]
A phase difference plate 20 and a polarizing plate 21 are provided in this order from the substrate side on the outer surface side of the lower substrate 4, and a backlight 3 is provided on the outer surface side of the polarizing plate 21. The backlight 3 includes a light source 22 such as a cold cathode tube and a light emitting diode (LED), a reflection plate 23, and a light guide plate 24. A front scattering plate 25, a retardation plate 26, and a polarizing plate 27 are provided in this order from the substrate 5 side on the outer surface side of the upper substrate 5.
[0022]
The arrangement of the electrodes on each of the substrates 4 and 5 is as follows. That is, the scanning electrodes 17 extending in the x direction are formed in stripes on the lower substrate 4, while a plurality of scanning electrodes 17 extending in the y direction so as to intersect the scanning electrodes 17 are formed on the upper substrate 5. The signal electrode 9 is formed in a stripe shape. Here, the R, G, and B dye layers 13R, 13G, and 13B of the color filter 13 are arranged corresponding to the extending direction of each signal electrode 9, as shown in FIG. That is, the color filter 13 in the present embodiment has a pattern called a so-called vertical stripe, and the R, G, and B dye layers 13R, 13G, and 13B are arranged in stripes in the same color vertically. As a result, one pixel 29 constituting a display pattern is formed by the three dots R, G, B of R, G, B arranged in the horizontal direction shown in FIG. Note that a dot means a portion where each scanning electrode 17 and each signal electrode 9 intersect, and means a minimum unit portion of display.
[0023]
Here, the configuration of the color filter 13 provided in the liquid crystal display device 1 of the present embodiment will be described in more detail. First, the color filter 13 includes the R, G, and B dye layers 13R, 13G, and 13B as described above, and the dots 28R, 28G, and 28B are configured corresponding to the dye layers 13R, 13G, and 13B. These three dots 28R, 28G, and 28B constitute a pixel.
[0024]
In the present embodiment, as shown in FIG. 1, each of the dots 28R, 28G, and 28B includes the formation region 8a of the reflection film 8 and the non-formation region 8b of the reflection film 8, that is, one dot. The liquid crystal display device includes a reflective display area (8a) and a transmissive display area (8b). Here, the planar area of the region 8b where the reflective film 8 is not formed, that is, the transmissive display region (8b), is the smallest among the green dots 28G among the dots 28R, 28G, and 28B. When the area of the transmissive display area (8b) is TR, TG, TB corresponding to the dots 28R, 28G, 28B, 0.20 <(TG / (TR + TG + TB)) <0.33 is satisfied. An opening (that is, a non-formation region 8 b) is formed in the reflective film 8.
[0025]
In the present embodiment, the dye layers 13R, 13G, and 13B of the color filter 13 are not provided throughout the dots 28R, 28G, and 28B, but are provided on the dye layers 13R, 13G, and 13B. Is provided with an opening 31 for each of the dots 28R, 28G, and 28B. That is, the opening 31 is a non-colored region formed in the color filter 13, and is formed as a non-colored region 31R, 31G, 31B for each of the dye layers 13R, 13G, 13B. Therefore, each of the dots 28R, 28G, and 28B includes the colored regions 30R, 30G, and 30B of the color filter 13 and the non-colored regions 31R, 31G, and 31B, as shown in FIG. Become. In particular, in this embodiment, the non-colored areas 31R, 31G, and 31B are selectively provided in the reflective display area (8a), and the non-colored areas 31R, 31G, and 31B are provided in the transmissive display area (8b). Not formed.
[0026]
Here, the area where the colored regions 30R, 30G, 30B of the color filter 13 and the reflective display region (8a) on which the reflective film 8 is formed overlaps on the plane (overlapping area) is the dot 28R, 28G, 28B. Among them, the green dot 28G is the smallest, and when the overlapping area is specifically set to RR, RG, RB corresponding to each dot 28R, 28G, 28B, 0.26 <(RG / (RR + RG + RB) ) <0.33.
[0027]
Furthermore, in the present embodiment, the area of one dot is the smallest among the green dots 28G among the dots 28R, 28G, and 28B. Specifically, the dot area is set to the dots 28R, 28G, and 28B. When SR, SG, and SB are set to correspond to the above, 0.26 <(SG / (SR + SG + SB)) <0.33 is satisfied.
[0028]
The liquid crystal display device 1 configured as described above is configured as a transflective color liquid crystal display device capable of switching between reflective display and transmissive display. A part of the external light incident from the upper substrate 5 side in the reflection mode is transmitted through the non-colored regions 31R, 31G, 31B in the reflective display region (8a). Accordingly, the light obtained by passing through the color filter 13 twice in the reflection mode is the uncolored light that passes through the non-colored regions 31R, 31G, and 31B and the colored regions 30R and 30G in the reflective display region (8a). , 30B and the colored light transmitted through 30B are superimposed.
[0029]
On the other hand, all the light transmitted from the backlight 3 through the transmissive display region (8b) in the transmissive mode is transmitted through the colored regions 30R, 30G, and 30B, and is obtained by passing through the color filter 13 once in the transmissive mode. All the light emitted is colored light. In this way, it is possible to reduce the color difference between the light obtained by transmitting twice through the color filter 13 in the reflection mode and the light obtained by transmitting once through the color filter 13 in the transmission mode. By optimizing the dye layers 13R, 13G, and 13B of the color filter 13, it is possible to obtain a display with high visibility and good visibility in both the reflection mode and the transmission mode.
[0030]
That is, since the area of the transmissive display area (8b) in one dot is minimized in the green dot 28G configured by the green dye layer 13G, the color display of the green display is not deteriorated, particularly in the white display. In the transmissive display area (8b), yellowish green coloration could be prevented or suppressed. Further, since the areas of the colored regions 30R, 30G, and 30B in the reflective display region (8a) are minimized in the green dots 28G formed by the green pigment layer 13G, the reflective display region ( It was possible to prevent or suppress the occurrence of yellowish green coloring in 8a).
[0031]
As described above, in the present embodiment, in the green dots 28G configured to correspond to the green pigment layer 13G, the reflective display in which the area of the transmissive display region (8b) also overlaps with the colored region of the color filter 13 in a plane. The area of the region (8a) is also configured to be the smallest among the dots 28R, 28G, and 28B. Here, for example, if the areas SR, SG, and SB of one dot are the same, in the green dot 28G, the area of the reflective display area (8a) that does not overlap with the colored area becomes large. There may be a problem that the green color becomes worse. However, since the area of the green dot 28G is minimized in the present embodiment, the area of the reflective display region (8a) that does not overlap with the colored region can be made relatively small, and good green color development can be achieved in reflective display. It became possible to get.
[0032]
As described above, in the present embodiment, the above-described configuration is adopted for the green dot 28G. Therefore, the reflective display and the transmissive display have a small color density difference, and the white display displays a little yellow-green color. It became possible. Since green light has much higher visibility for human eyes than red light and blue light, the area of the dots 28G corresponding to the green pigment layer is minimized as in this embodiment. Even when set, the color reproducibility and brightness when viewed as a whole can be sufficiently ensured.
[0033]
In the present embodiment, a metal film having a high light reflectivity such as aluminum or an alloy thereof, silver or an alloy thereof is adopted as the reflecting film 8 that reflects external light such as natural light incident from the upper substrate 5 side. For example, it is possible to employ a reflective polarizing film 80 as shown in FIG. FIG. 2 schematically shows the configuration of the reflective polarizing plate 80. The reflective polarizing plate 80 is arranged in a stripe pattern on a light-transmitting base material 81A such as an acrylic substrate or a glass substrate. A lattice 82 made of a plurality of metal films is provided. FIG. 3 is a plan view of the reflective polarizing plate 80, and the pitch P of the grating 82 is set to a value smaller than the wavelength of the incident light, for example, about 40 nm to 200 nm. The width of the grating 82 is set to, for example, about 20 nm to 100 nm, which is convenient for manufacturing, but is more preferably about 1/10 of the wavelength of incident light. In addition, as a material of the lattice 82, for example, a metal material such as aluminum is used.
[0034]
FIG. 4 is an explanatory diagram showing the operation of the reflective polarizing plate 80, and in the reflective polarizing plate 80, the refractive index n of the grating 82 is shown. _A And the refractive index n of the insulating layer 81B interposed between the lattices 82. _B Therefore, the polarization selection is performed according to the polarization direction of the light incident on the reflective polarizing plate 80. Specifically, the linearly polarized light X having the polarization axis in the direction perpendicular to the extending direction of the metal film is transmitted, and the linearly polarized light Y having the polarization axis in the direction parallel to the extending direction of the metal film is reflected. Therefore, the reflective polarizing plate 80 has a function of transmitting polarized light parallel to the optical axis (transmission axis) and reflecting perpendicular polarized light, and the reflective film of the liquid crystal display device 1 of the present embodiment. 8 can be applied.
[0035]
As mentioned above, although one embodiment of the liquid crystal display device of the present invention has been shown, the present invention is not limited to this, and various modifications can be made within the scope of the matters described in the claims. It is. For example, in the liquid crystal display device 1, the color filter 13 is disposed on the inner surface side of the lower substrate 4, but it can be formed on the inner surface side of the upper substrate 5. Further, in the liquid crystal display device 1, the front scattering plate 25 is disposed on the outer surface side of the upper substrate 5. However, the front scattering plate 25 is omitted, and an uneven film is formed on the inner surface of the substrate, and a metal film is formed thereon. By providing, a light scattering effect may be given.
[0036]
[Second Embodiment]
Hereinafter, a second embodiment of the present invention will be described with reference to FIG.
FIG. 5 is a plan view (a) and a cross-sectional view (b) showing a schematic configuration of the liquid crystal display device 100 of the second embodiment, corresponding to FIG. 1 of the first embodiment. . The liquid crystal display device 1 according to the first embodiment shown in FIG. 1 is a passive matrix type liquid crystal display device, whereas the liquid crystal display device according to the present embodiment is an active matrix type liquid crystal display device having a switching element. It is a liquid crystal display device. Therefore, the basic configuration of the liquid crystal display device 100 of the present embodiment is the same as that of the first embodiment, and mainly the electrode configuration and the formation position of the color filter are different from those of the first embodiment. Therefore, in FIG. 5, the same components as those in FIG.
[0037]
In the liquid crystal display device 100 shown in FIG. 5, a pixel driving wiring 83 including a TFT element is formed on the inner surface side of the lower substrate 4, and further on the inner surface side through the insulating film 72 and the reflective film 8. The pixel electrode 71 is formed of a transparent electrode made of ITO or the like formed so as to cover the reflective film 8, and the alignment film 18 is formed on the pixel electrode 71. On the other hand, on the inner surface side of the upper substrate 5, the color filter 13, an overcoat layer 16 covering the color filter 13, a flat solid common electrode 91 made of a transparent electrode such as ITO, and an orientation formed on the common electrode 91. A liquid crystal layer 7 is sandwiched between the alignment films 11 and 18. As shown in FIG. 5A, the pixel electrode 71 is connected with a thin film transistor (TFT) 76 as a switching element for each dot 28R, 28G, 28B.
[0038]
Also in such a liquid crystal display device 100, the area of the transmissive display area (8 b) in each dot and the area of the reflective display area (8 a) that overlaps with the colored area of the color filter 13 in a plane are set to each dot 28 R, 28G and 28B are configured such that the green dot 28G is minimized, and the area of the green dot 28G is also minimized with respect to the dot area, so that the reflective display region (8a) that does not overlap with the colored region of the color filter. The area can be made relatively small, and a good green color can be obtained in reflective display.
[0039]
That is, in the active matrix type liquid crystal display device 100 as well, by adopting the above-described configuration for the green dots 28G, there is little difference in color density in both the reflective display and the transmissive display, and the yellow-green color is displayed in the white display. A display with little coloring can be performed. Also in this case, if the area of the transmissive display area (8a) in one dot is TR, TG, TB corresponding to each of the dye layers 13R, 13G, 13B, 0.20 <(TG / ( TR + TG + TB)) <0.33 is preferably satisfied, and the area in which the color filter 13 and the reflective display region (8a) overlap on a plane is set to RR, RG, RB corresponding to each of the dye layers 13R, 13G, 13B. In this case, it is preferable that 0.26 <(RG / (RR + RG + RB)) <0.33 is satisfied. Furthermore, when the area of one dot is SR, SG, SB corresponding to each of the dye layers 13R, 13G, 13B, it is preferable that 0.26 <(SG / (SR + SG + SB)) <0.33 is satisfied.
[0040]
[Third Embodiment]
Hereinafter, a third embodiment of the present invention will be described with reference to FIG.
FIG. 6 is a plan view (a) and a cross-sectional view (b) showing a schematic configuration of the liquid crystal display device 110 of the third embodiment, corresponding to FIG. 1 of the first embodiment. . The liquid crystal display device 1 of the first embodiment shown in FIG. 1 uses ITO as the electrodes provided on the inner surfaces of the upper and lower substrates, whereas the liquid crystal display device 110 of the present embodiment uses the upper substrate. Although ITO was used as the electrode formed on the side, a sandwich structure was formed in which the reflective layer 8 was formed on the ITO 71 and covered with the ITO 71 as the electrode formed on the inner surface side of the lower substrate 4 to reduce the electrode resistance. Therefore, the basic configuration of the liquid crystal display device 110 of the present embodiment is the same as that of the first embodiment, and the configuration of the reflective film and the electrodes is mainly different from that of the first embodiment. Therefore, in FIG. 6, the same components as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.
[0041]
The liquid crystal display device 110 shown in FIG. 6 includes a signal electrode ITO 71 and an alignment film 18 formed on the ITO 71 on the inner surface side of the lower substrate 4. In this case, the reflection film 8 is made of a metal film having a high light reflectivity such as aluminum or an alloy thereof, silver or an alloy thereof, and is formed so as to extend in a direction perpendicular to the paper surface.
[0042]
On the other hand, on the inner surface side of the upper substrate 5, the color filter 13, the overcoat layer 16 covering the color filter 13, the stripe-shaped scanning electrode 92 made of a transparent electrode such as ITO, and the alignment film formed on the scanning electrode 92 11 are formed. The scanning electrode 92 is formed so as to extend in a direction parallel to the paper surface, and the liquid crystal layer 7 is sandwiched between the alignment films 11 and 18 of each substrate.
[0043]
As described above, in the liquid crystal display device 110 according to the present embodiment, since the reflective film 8 is formed in a stripe shape and the ITO 71 sandwiches the reflective film, the reflective film 8 is formed between the individual reflective films 8 in the stripe shape. A region including only the slit-like ITO 71 constitutes a transmissive display region.
[0044]
Also in such a liquid crystal display device 100, the area of the transmissive display area (8 b) in each dot and the area of the reflective display area (8 a) that overlaps with the colored area of the color filter 13 in a plane are set to each dot 28 R, 28G and 28B are configured such that the green dot 28G is minimized, and the area of the green dot 28G is also minimized with respect to the dot area, so that the reflective display region (8a) that does not overlap with the colored region of the color filter. The area can be made relatively small, and a good green color can be obtained in the reflective display.
[0045]
[Electronics]
Examples of electronic devices provided with the liquid crystal display device of the above embodiment will be described.
FIG. 7 is a perspective view showing an example of a mobile phone. In FIG. 7, reference numeral 1000 denotes a mobile phone body, and reference numeral 1001 denotes a liquid crystal display unit using the liquid crystal display device. Since such an electronic device includes the liquid crystal display unit using the liquid crystal display device of the above-described embodiment, the color is good in both the reflection mode and the transmission mode, and a display with little coloration and excellent visibility is provided. An electronic device can be realized.
[0046]
(Example)
Next, in order to confirm the effect of the liquid crystal display device of the present embodiment, the following measurements were performed.
First, for the liquid crystal display device having the configuration of FIG. 1, liquid crystal display devices of Examples 1 to 7 and Comparative Examples 1 and 2 having different configurations of the color filter 13 were prepared. Specifically, as shown in Table 1, for each of the dots 28R, 28G, and 28B corresponding to the dye layers 13R, 13G, and 13B, the areas SR, SG, and SB are variously set, while the transmissive display area (8a ), Areas TR, TG, and TB were also set. In addition, the liquid crystal display devices of Examples 1 to 7 and Comparative Examples 1 and 2 were prepared for the dots 28R, 28G, and 28B with different areas overlapping with the reflective display region (8b).
[0047]
[Table 1]

[0048]
In addition, about the kind of color filter, as shown in Table 2, about the comparative example 1 and Examples 1-7, the same thing of reflectance Y and chromaticity x, y is used, and comparative example 2 is these comparative examples. 1 and Examples 1 to 7 were different in reflectance Y and chromaticity x, y.
[0049]
[Table 2]

[0050]
And about the liquid crystal display device of these Comparative Examples 1-2 and Examples 1-7, the reflectance and color gamut area at the time of reflective display were measured, and the transmittance | permeability and color gamut area were also measured at the time of transmissive display. Here, the color gamut area is an area of a triangle connecting points when the display colors of red, green, and blue are represented by (x, y) coordinates on the CIE chromaticity diagram.
[0051]
As can be seen from Table 1, the liquid crystal display device of Comparative Example 2 suppresses coloring of the white display color of reflection and transmission by using a color filter with low color purity as a green color filter as shown in Table 2 in green dots. Therefore, the color gamut area during transmissive display is reduced. Therefore, when the color filter type is changed as in Comparative Example 1 as shown in Table 2, the color gamut area during transmissive display is increased, but the white display during transmissive display and reflective display is yellowish green. Colored. Therefore, by reducing the area ratio of the transmissive display region in the green dots as in Example 1, it was possible to suppress the yellow-green coloring of the white display while maintaining the green coloration during the transmissive display. Furthermore, since the area ratio of the reflective display region for the green dots was reduced by reducing the green dot area ratio, yellow-green coloring in white display during reflective display could be suppressed.
[0052]
Furthermore, in the liquid crystal display devices of Examples 2 to 4, a region without a color filter was formed in the green dot reflection display region. That is, the non-colored region of the color filter is formed in the green dot reflective display region. In Example 2, white display at the time of reflective display is somewhat sacrificed, and in Example 3, white display at the time of transmissive display is somewhat sacrificed, but in Example 4, the portion without the color filter in the reflective display region is green. In addition to the dots, red and blue dots are also provided to improve coloration in white display as in the second and third embodiments. In the case of Example 4, the color gamut area at the time of reflective display is sacrificed, but the color gamut area is prioritized in terms of image quality in the transmissive display, whereas the brightness is higher than the color gamut area in the reflective display. Takes precedence.
[0053]
For the liquid crystal display device of Example 5, the area ratio of the green dots and the area ratio of the reflective display area that overlaps the color filter in the green dots (area ratio with the green reflective portion color filter) are very high. Since it was made small, yellow-green coloring in white display could be suppressed, but the color gamut area during reflection display was very small. Further, in the liquid crystal display device of Example 6, since the area ratio of the transmissive display region with respect to green dots was very small, it was possible to suppress white display coloring during transmissive display, but the transmissive display color gamut. The area was very small. Furthermore, in the liquid crystal display device of Example 7, since the area ratio of the reflective display region that overlaps the color filter in the green dots was very small, coloring of white display during reflective display could be suppressed. The display color gamut area is very small.
[0054]
Therefore, in order to suppress white display coloring, the dot area SG, the transmissive display area TG, and the overlapping area RG of the reflective display area and the color filter are relatively smaller than the dots of other colors. It is preferable to set the color gamut area to a predetermined value (for example, 1.1 × 10 ^-2 In order to secure the above, 0.20 <(TG / (TR + TG + TB)) <0.33 for the transmissive display area TG and 0.26 <(RG / (RR + RG + RB)) <0 for the overlapping area RG. .33, and the dot area SG preferably satisfies 0.26 <(SG / (SR + SG + SB)) <0.33. However, for example, if the reflectance is 22% or more, the color gamut area of reflection is 0.9 × 10 ^-2 Since the reflection is also good in the above, the overlapping area RG should satisfy 0.20 <(RG / (RR + RG + RB)) <0.33.
[Brief description of the drawings]
1A and 1B are a plan view and a cross-sectional view showing a schematic configuration of a liquid crystal display device according to a first embodiment.
FIG. 2 is a perspective view schematically showing an example of a reflective film.
3 is a plan view of the reflective film in FIG. 2. FIG.
4 is an explanatory view showing the operation of the reflective film of FIG. 2;
5A and 5B are a plan view and a cross-sectional view showing a schematic configuration of a liquid crystal display device according to a second embodiment.
6A and 6B are a plan view and a cross-sectional view showing a schematic configuration of a liquid crystal display device according to a third embodiment.
FIG. 7 is a perspective view illustrating an example of an electronic apparatus according to the invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Liquid crystal display device, 2 ... Liquid crystal cell, 3 ... Backlight (illumination means), 4 ... Lower substrate, 5 ... Upper substrate, 7 ... Liquid crystal layer, 8 ... Reflective film, 13 ... Color filter, 13R, 13G, 13B ... Dye layer, 28R, 28G, 28B ... dot, 29 ... pixel, 31R, 31G, 31B ... non-colored area

Claims (8)

A pair of substrates composed of an upper substrate and a lower substrate that are arranged opposite to each other, a liquid crystal layer sandwiched between the pair of substrates, and an inner surface of the lower substrate, and reflects incident light from the upper substrate side. A reflective layer, a color filter provided on the upper side of the reflective layer, in which red, green, and blue pigment layers are arranged corresponding to the dots constituting the display area; and provided on the outer surface side of the lower substrate. A transflective liquid crystal display device that performs display with a reflective region in which the reflective layer exists for each dot and a transmissive region in which the reflective layer does not exist,
The area of the transmissive region in one dot is minimized in the dots corresponding to the green pigment layer among the red, green, and blue pigment layers, while the colored region of the color filter and the reflective region are planar. The overlapping area is minimized for the dots corresponding to the green dye layer among the red, green, and blue dye layers, and the area of one dot is the green dye among the red, green, and blue dye layers. A liquid crystal display device characterized in that the number of dots corresponding to a layer is minimized. 2. The non-colored region of the color filter is included in at least a reflection region of a dot corresponding to the green pigment layer among the red, green, and blue pigment layers. Liquid crystal display device. When the area of the transmission region in one dot is TR, TG, TB corresponding to each of the red, green, and blue dye layers, 0.20 <(TG / (TR + TG + TB)) <0.33. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is satisfied. When the area where the colored region of the color filter and the reflective region overlap on the plane is RR, RG, RB corresponding to the red, green, and blue pigment layers, 0.26 <(RG / (RR + RG + RB). 4) The liquid crystal display device according to claim 1, wherein <0.33 is satisfied. When the area of one dot is SR, SG, SB corresponding to each of the red, green, and blue dye layers, 0.26 <(SG / (SR + SG + SB)) <0.33 is satisfied. The liquid crystal display device according to any one of claims 1 to 4. The liquid crystal display device according to claim 1, wherein the reflective layer is formed of a metal reflective film. The liquid crystal display device according to claim 1, wherein the reflective layer is a reflective polarizing layer in which fine slits are formed in a metal film. An electronic apparatus comprising the liquid crystal display device according to claim 1.

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