JP3545264B2 - Reflective liquid crystal display - Google Patents

Description

図２５（ａ）、図２５（ｂ）、図２６（ａ）、図２６（ａ）の結果に上記評価関数を適用し、縦軸に評価値Ｗを、横軸を印加電圧をとったものが、それぞれ図２７（ａ）、図２７（ｂ）、図２８（ａ）、図２８（ｂ）である。このグラフから評価値Ｗが大きくなるようなθ１の範囲を求めると、（θ２、θ３）の組み合わせによって異なるが、表１のような最適θ１を得ることができた。そして、この最適θ１の範囲は目視観察の結果とも一致した。
【０１０３】
【表１】

なお、本実施例では、上側基板のみにラビング処理を施した場合を示したが、下側基板のみにラビング処理を施した場合も同様な結果が得られた。
【０１０４】
また、本実施例では、光学位相差補償板の遅相軸の設定範囲を１０°の幅を持たせたが、この範囲内では実際に観察し、上の結果が保持されることも確認している。光学位相差補償板の種類については、一軸性位相差板もしくは二軸性位相差板の違い、負の位相差板の使用にかかわらず、上の結果が保持されることも確認している。
【０１０５】
【発明の効果】
以上の説明から明らかなように、本発明による反射型液晶表示装置では、反射率が高く、かつコントラストが高い反射型液晶表示装置を実現できる。さらに、反射板の反射膜形成面を透明基板の液晶層側に設置することができ、良好な暗状態を実現できる。よって、視差のない、高コントラストの高精細で動画表示が可能である。液晶層がツイストしているため、視野角特性に優れている。また、本装置に高明度に調整されたカラーフィルタを用いれば、良好な色再現性を有した表示品位の高いカラー反射型液晶表示装置を実現することができる。
【図面の簡単な説明】
【図１】２枚の光学位相差補償板を用いた場合の反射型液晶表示装置の構造断面図である。
【図２】２枚の光学位相差補償板を用いた場合の偏光板と光学位相差補償板の設定方位を示す平面図である。
【図３】実施形態１の反射型液晶表示装置における反射率と印加電圧の関係図である。
【図４】実施形態の反射型液晶表示装置における反射率測定の際の光学系の構成配置図である。
【図５】３枚の光学位相差補償板を用いた場合の反射型液晶表示装置の構造断面図である。
【図６】３枚の光学位相差補償板を用いた場合の偏光板と光学位相差補償板の設定方位を示す平面図である。
【図７】実施形態２の反射型液晶表示装置における反射率と印加電圧の関係図である。
【図８】実施形態２の反射型液晶表示装置におけると上基板上の液晶分子と下基板上の液晶分子とのなす角度と｜ｄ／ｐ｜の最適条件の関係図である。
【図９】実施形態３の反射型液晶表示装置における反射率と印加電圧の関係図である。
【図１０】実施形態５の反射型液晶表示装置における構造断面図である。
【図１１】実施形態４の反射型液晶表示装置における、（ａ）は一軸性光学位相差補償板を用いた場合、（ｂ）は二軸性光学位相差補償板を用いた場合の電圧無印加状態における表示面の輝度と表示面の方位角の関係図である。
【図１２】実施形態５の反射型液晶表示装置におけるコントラストと表示面の方位角の関係図である。
【図１３】実施形態６の反射型液晶表示装置における構造断面図である。
【図１４】評価関数による電圧３．５Ｖ（ａ）及び電圧を仮想的に無限大にしたとき（ｂ）のΔｎｄと３６０×｜ｄ／ｐ｜の関係図である。
【図１５】実施形態１の反射型液晶表示装置におけるコントラストの入射光方位角依存性の説明図である。
【図１６】実施形態１の反射型液晶表示装置における、偏光板１０の透過軸と上側基板４上の液晶分子の方向のなす角度が４５°（ａ）、１５０°（ｂ）の時の反射輝度の等高線図である。
【図１７】実施形態１の反射型液晶表示装置における、偏光板１０の透過軸と上側基板４上の液晶分子の方向のなす角度が０°（ａ） 、９０°（ｂ）の時の反射輝度の等高線図である。
【図１８】実施形態１の反射型液晶表示装置における、偏光板１０の透過軸と上側基板４上の液晶分子の方向のなす角度が１３５°（ａ）および１６５°（ｂ）の時の反射輝度の等高線図である。
【図１９】実施形態１の反射型液晶表示装置における、（ａ）は液晶層のΔｎｄを３５０ｎｍに、（ｂ）は液晶層のΔｎｄを２００ｎｍにした時の評価関数による印加電圧と３６０ ｜ｄ／ｐ｜の関係図である。
【図２０】上基板上の液晶分子の配向方向と下基板上の液晶分子の配向方向のなす角度を（ａ）４５°、（ｂ）２７０°とした時の、評価関数によるΔｎｄと３６０｜ｄ／ｐ｜の関係図である。
【図２１】実施形態３の反射型液晶表示装置における、上基板上の液晶分子の配向方向と下基板上の液晶分子の配向方向のなす角度を２２５°とし、｜ｄ／ｐ｜を（ａ）０．１，（ｂ）０．３とした時の、評価関数によるΔｎｄと印加電圧の関係図である。
【図２２】実施形態３の反射型液晶表示装置における、上基板上の液晶分子の配向方向と下基板上の液晶分子の配向方向のなす角度を２２５°とし、｜ｄ／ｐ｜を（ａ）０．５、（ｂ）０．７とした時の、評価関数によるΔｎｄと印加電圧の関係図である。
【図２３】実施形態７の反射型液晶表示装置におけるコントラストと入射光の入射方位角の関係図である。
【図２４】実施形態７の反射型液晶表示装置におけるコントラストと入射光の入射方位角の関係図である。
【図２５】実施形態８の反射型液晶表示装置における階調表示を行った時の色度をＬ＊ａ＊ｂ＊表示した図である。
【図２６】実施形態８の反射型液晶表示装置における階調表示を行った時の色度をＬ＊ａ＊ｂ＊表示した図である。
【図２７】実施形態８の反射型液晶表示装置における階調表示を行った時の色度を式１による評価関数と電圧の関係で表示した図である。
【図２８】実施形態８の反射型液晶表示装置における階調表示を行った時の色度を式１による評価関数と電圧の関係で表示した図である。
【符号の説明】
１ 液晶層
２ 垂直配向膜
３ 垂直配向膜
４ 第２の基板
５ 第１の基板
６ 電極
７ 反射性電極
８ 第１の光学位相差補償板
９ 第２の光学位相差補償板
１０ 偏光板
１１ 第３の光学位相差補償板
１２ 偏光板透過方位
１３ 第１の光学位相差補償板の遅相軸方位
１４ 第２の光学位相差補償板の遅相軸方位
１５ 第３の光学位相差補償板の遅相軸方位
１６ 第２の基板上の液晶配向の方位（配向処理方向）
１７ 第１の基板上の液晶配向の方位（配向処理方向）
１８ 本発明の実施形態３に記載の反射型液晶表示装置
２９ 負の屈折率異方性の光学位相差補償板
３０ 液晶・高分子複合層
３１ 高分子[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a reflection type liquid crystal display device which is used in office automation (OA) devices such as a word processor and a notebook personal computer, various video devices and game devices, and does not use a direct-view backlight.
[0002]
[Prior art]
At present, liquid crystal display devices are frequently used as color displays having characteristics such as thinness and light weight. A particularly widely used color liquid crystal display device is a transmission type liquid crystal display device using a light source as a background, and its use is expanding in various fields.
[0003]
In contrast to this transmission type liquid crystal display device, a reflection type liquid crystal display device which is another display method does not require a backlight, so that power for a light source can be reduced, and further, space and weight of the backlight can be saved. And so on. That is, power consumption can be reduced as a whole of the display device, a small battery can be used, and the display device is suitable for a device that is lightweight and thin. Alternatively, if the devices are manufactured so as to have the same size or weight, a drastic increase in operation time can be expected by using the devices for a large battery.
[0004]
Also, from the viewpoint of the contrast characteristics of the display surface, in a CRT or the like which is a light-emitting display device, a significant decrease in contrast ratio is observed outdoors in the daytime, or a transmissive liquid crystal display device subjected to low reflection processing. Also, when the ambient light such as under direct sunlight is much stronger than the display light, a significant decrease in the contrast ratio cannot be avoided. On the other hand, the reflective liquid crystal display device obtains display light proportional to the amount of ambient light, and is particularly suitable for outdoor use such as portable information terminal equipment, digital cameras, and portable video cameras.
[0005]
Despite having such promising application fields as mentioned above, sufficient contrast ratio, reflectance, multi-color, high-definition display, and compatibility with moving images, etc. are insufficient, so that sufficient practical use up to the present There is no reflective color liquid crystal display device having a characteristic.
[0006]
Hereinafter, the reflective liquid crystal display device will be described in more detail. ◆
A conventional twisted nematic (hereinafter abbreviated as TN) type liquid crystal display device has a configuration using two polarizing plates, and is excellent in contrast ratio and viewing angle dependent characteristics, but inevitably has low reflectance. . Further, since the distance between the liquid crystal modulation layer and the light reflection layer is apart by the thickness of the substrate or the like, parallax occurs due to a shift in the optical path between the time of incidence and reflection of the illumination light.
[0007]
In particular, in a configuration used for a normal transmissive liquid crystal display, in which a color filter in which different pixels are provided for each color element is combined with a single liquid crystal modulation layer, the color element that passes at the time of incidence and reflection depends on the traveling direction of light. Unlike the case where is inclined, it is not suitable for high-resolution and high-definition display of color. For these reasons, reflective color display using this display mode has not been put to practical use.
[0008]
On the other hand, guest-host type liquid crystal devices (hereinafter abbreviated as GH) in which a dye is added to liquid crystal without using a polarizing plate or using only one sheet have been developed. However, there is a problem in that the dye has a low dichroic ratio and a high contrast ratio cannot be obtained due to a low dichroic ratio. In particular, lack of contrast significantly reduces color purity in color display using a color filter, so it is necessary to combine the color filter with a color filter having a high color purity. However, there is a problem that the advantage of high brightness of the present system due to the absence of a polarizing plate is impaired.
[0009]
Against this background, a liquid crystal display element using a single polarizing plate (hereinafter, referred to as a single polarizing plate method) that can be expected to provide high resolution and high contrast display has been developed. Among them, many examples of the combination with a quarter-wave plate capable of realizing high contrast are disclosed.
[0010]
As one example, JP-A-55-48733 discloses a reflective TN (45 ° twist type) liquid crystal display device using one polarizing plate and a １ ／ wavelength plate. In this prior art, a 45 ° twisted liquid crystal layer is used to control the applied electric field so that the plane of polarization of the incident linearly polarized light is in a state parallel to the optical axis of the 波長 wavelength plate and in a 45 ° twisted state. And black and white display is performed by realizing the two states of The configuration of this liquid crystal cell includes a polarizer, a 45 ° twist liquid crystal layer, a 波長 wavelength plate, and a reflector from the incident light side.
[0011]
Further, US Pat. No. 4,701,028 (Clerc et al.) Discloses a reflective liquid crystal display device in which one polarizing plate, a quarter-wave plate, and a vertically aligned liquid crystal cell are combined. Japanese Patent Application Laid-Open No. 6-337421 discloses a reflective liquid crystal display device in which one polarizing plate, a quarter-wave plate, and a bend vertical alignment liquid crystal cell are combined. Also, Euro Display # 96 (P.464) discloses a reflective liquid crystal display device in which one polarizing plate, a １ ／ wavelength plate, and a vertical alignment liquid crystal cell are combined.
[0012]
SID96 DIGEST (P. 763) describes a display mode in which a liquid crystal with a negative dielectric anisotropy and a chiral dopant added is sandwiched between upper and lower substrates subjected to a vertical alignment process. Application examples are disclosed.
[0013]
The display operation of the single polarizing plate system disclosed in JP-A-6-337421 will be described. ◆
The polarizing plate disposed on the incident side has a function of passing only one direction of the linear components of the polarized light of the incident light and the emitted light, and absorbing the light of the other direction. The incident light that has passed through the polarizing plate is converted into circularly polarized light by an optical phase difference compensating plate such as a λ / 4 plate, enters the liquid crystal layer, passes through the vertically aligned liquid crystal layer, and reaches the reflecting plate as it is. The light arriving at the reflector is converted by the reflector into circularly opposite polarized light, passes through the liquid crystal layer, the λ / 4 plate, etc. in the reverse order of the time of incidence to become linearly polarized light orthogonal to the linearly polarized light at the time of incidence. , A dark state is realized.
[0014]
In addition, when the liquid crystal layer is tilted by applying a voltage and a phase difference under a certain condition is developed, the incident circularly polarized light that has passed through the polarizing plate is converted into linearly polarized light, and the reflected light becomes linearly polarized light as it is. Is obtained, and a bright polar bear is realized. ◆ In other words, the necessary and sufficient conditions for realizing these states for light that enters and exits the liquid crystal display device perpendicularly are as follows: For a bright bear, the polarization state on the reflector is a straight line in any direction. It is already known that the light becomes polarized light, and that it becomes right or left circularly polarized light on the reflector in the dark state.
[0015]
[Problems to be solved by the invention]
However, in the liquid crystal display device disclosed in Japanese Patent Application Laid-Open No. 55-48733, it is necessary to provide a 波長 wavelength plate between the liquid crystal layer and the reflection plate. It is difficult to form a film and is not suitable for high resolution and high definition display.
[0016]
The following problems are encountered in the vertical alignment type reflection type liquid crystal display device described in US Pat. No. 4,701,028, US Pat. No. 4,492,432, JP-A-6-337421, and Euro Display # 96 (p. 464). There is. ◆
First, the direction of the vertical alignment, particularly the tilted vertical alignment, is parallel between the upper and lower substrates, and the liquid crystal falls in one direction, and the viewing angle dependence in the plane is extremely large. Further, there is a problem that the liquid crystal is colored due to a large wavelength dependence of the reflectance due to the wavelength dispersion of the refractive index of the liquid crystal.
[0017]
In addition, the SID96 DIGEST p. In the display mode described in 763, linearly polarized light is incident using a polarizing beam splitter without using a quarter-wave plate, and is not applied to a direct-view type. Furthermore, there is no mention of the detailed setting of | d / p | when the natural pitch of the liquid crystal is p and the cell thickness is d, and the optimum Δn * d (birefringence difference * liquid crystal layer thickness).
[0018]
SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a reflective liquid crystal display device having a high reflectance, a high contrast, and an excellent viewing angle characteristic.
[0019]
[Means for Solving the Problems]
In order to achieve the above object, the present inventors have proposed a single-polarizer system capable of realizing a high-resolution display with a configuration that does not cause parallax, on a reflector required to realize a bright state and a dark state. As a result of various studies on means capable of electrically switching different polarization states, a polarizing plate and an optical phase difference compensating plate are configured so as to realize a dark state of the liquid crystal display element without applying a voltage to the liquid crystal layer. It is necessary to realize a good dark state without requiring high precision in the manufacturing process of the liquid crystal layer.
[0020]
Further, they have found that it is necessary to set the retardation of the liquid crystal layer and the value of | d / p | to special values in order to obtain a good bright state when a voltage is applied. Further, the inventors have found out the configurations of a polarizing plate and an optical retardation compensator that realize such a polarization state, and have found a configuration of a liquid crystal layer that realizes an optimal display using them.
[0021]
That is, the first invention of the present application is directed to a first substrate having a light-reflective electrode, a transparent second substrate having a transparent electrode, and a dielectric substrate sandwiched between the first substrate and the second substrate. A nematic liquid crystal layer having negative anisotropy and twisting in response to voltage application; and a plurality of optical phase difference compensators provided on the second substrate for allowing circularly polarized light to enter the liquid crystal layer. And at least one of the first and second substrates has an angle of at least 0 ° and less than 10 ° with respect to a normal direction of the substrate. When the natural pitch of the liquid crystal is p, the liquid crystal layer thickness is d, and the birefringence difference of the liquid crystal is Δn,
0 <| d / p | ≦ 0.7 and 135 nm ≦ Δnd ≦ 1200 nm
The natural pitch of the liquid crystal, the thickness of the liquid crystal layer, and the difference in the birefringence of the liquid crystal are selected so that the following holds.
[0022]
With this configuration, it is possible to realize good black display in a state where no voltage is applied and good white display in a state where a voltage is applied. That is, the viewing angle dependency can be improved by configuring the liquid crystal layer to be vertically aligned well when no voltage is applied and to be twisted when voltage is applied.
[0023]
In addition, by setting the values of Δnd and d / p of the liquid crystal layer to certain special values, a good bright state can be realized in a wide wavelength range, that is, a good white display can be expressed. Here, the present inventors set the lower limit of Δnd of the liquid crystal layer to 135 nm. This is because when the center wavelength of visible light is 540 nm, a good bright display is obtained, that is, when the liquid crystal layer has an incident circle. This is because the minimum retardation that can have an optical action of converting polarized light into linear polarized light on the reflector is 135 nm, which is one quarter of the center wavelength.
[0024]
With respect to the upper limit of 1200 nm, Δn of the liquid crystal composition is such that the upper limit of Δn is limited to about 0.18 due to low-temperature storage stability, and the liquid crystal layer thickness d is the response speed based on the response characteristics for rewriting the display of the liquid crystal display device. Is set to a practical value, the upper limit is about 7 μm, and the upper limit of Δnd is based on the product of these, about 1.2 μm (1260 nm).
[0025]
Furthermore, the second invention of the present application provides a first substrate having a light-reflective electrode, a transparent second substrate having a transparent electrode, and a dielectric substrate sandwiched between the first substrate and the second substrate. A nematic liquid crystal layer having negative anisotropy and twisting in response to voltage application; and a plurality of optical phase difference compensators provided on the second substrate for allowing circularly polarized light to enter the liquid crystal layer. In a reflection type liquid crystal display device comprising a plurality of polarizing plates, only liquid crystal molecules on one of the first and second substrates are uniformly aligned in a state of being inclined at a certain angle from a normal direction of the substrate. Have the nature
When the natural pitch of the liquid crystal is p, the liquid crystal layer thickness is d, and the birefringence difference of the liquid crystal is Δn,
0.22 ≦ | d / p | ≦ 0.42 and 200 nm ≦ Δnd ≦ 650 nm
The natural pitch of the liquid crystal, the thickness of the liquid crystal layer, and the difference in the birefringence of the liquid crystal are selected so that the following holds.
[0026]
Alternatively, the third invention of the present application relates to a first substrate having a light reflective electrode, a transparent second substrate having a transparent electrode, and a dielectric substrate sandwiched between the first substrate and the second substrate. A nematic liquid crystal layer having negative anisotropy and twisting in response to voltage application; and a plurality of optical phase difference compensators provided on the second substrate for allowing circularly polarized light to enter the liquid crystal layer. In a reflection type liquid crystal display device comprising a plurality of polarizing plates, only liquid crystal molecules on one of the first and second substrates are uniformly aligned in a state of being inclined at a certain angle from a normal direction of the substrate. Have the nature
When the natural pitch of the liquid crystal is p, the liquid crystal layer thickness is d, and the birefringence difference of the liquid crystal is Δn,
0.14 ≦ | d / p | ≦ 0.34 and 135 nm ≦ Δnd ≦ 350 nm
The natural pitch of the liquid crystal, the thickness of the liquid crystal layer, and the difference in the birefringence of the liquid crystal are selected so that the following holds.
[0027]
As described above, with the configuration of the liquid crystal layer according to the second or third aspect of the present invention, good display by uniform black and white display is realized. As a result, it was found that a good display could be obtained without necessarily performing the rubbing treatment on both the upper and lower substrates. In particular, in the configuration of the second invention, low-voltage driving, that is, low power consumption driving is possible, and in the configuration of the third invention, it is possible to greatly improve the viewing angle characteristics, and more excellent display is achieved. Was obtained.
[0028]
Further, in the fourth invention of the present application, the angle formed between the orientation direction of the liquid crystal molecules on the first or second substrate and the direction of the absorption axis of the polarizing plate disposed on the first substrate is θ1. In this case, it is characterized by 90 ° ≦ θ1 ≦ 165 °, and by adopting such a liquid crystal layer configuration, the azimuth in the display surface of the reflective liquid crystal display device is isotropically good. The display was found to be realized.
[0029]
Further, the fifth invention of the present application is directed to a liquid crystal display device according to the fifth aspect, wherein the angle between the orientation direction of the liquid crystal molecules on the first or second substrate and the direction of the absorption axis of the polarizing plate disposed on the first substrate is θ1. In this case, -15 ° ≦ θ1 ≦ 90 °, and when such a liquid crystal layer is formed, particularly excellent display is achieved in a direction having an azimuth angle in the display surface of the reflective liquid crystal display device. I found that I could get
[0030]
Further, when the rubbing process is performed on both the upper and lower substrates, the sixth invention of the present application is directed to a case where the liquid crystal molecules on both the first and second substrates are inclined at a certain angle from the normal direction to the substrates. It has uniform orientation in the state, and the angle between the liquid crystal molecules on the upper substrate and the orientation direction of the liquid crystal molecules on the lower substrate is defined as θ (however, the counterclockwise direction viewed from the molecules on the upper substrate is Positive),
0 ° ≦ θ ≦ 200 ° or 250 ° ≦ θ ≦ 360 ° and
By the feature that 200 nm ≦ Δnd ≦ 650 nm, a favorable display with uniform black-and-white display is realized.
[0031]
Further, in addition to the reflection type liquid crystal display device according to the sixth aspect, the device according to the seventh aspect has a value of | d / p | when the natural pitch of the liquid crystal is p and the thickness of the liquid crystal layer is d. When the angle between the liquid crystal molecules on the substrate and the liquid crystal molecules on the lower substrate is smaller than 225 °,
When the relational expression of | d / p | = -θ / 1000 + 0.40 ± 0.1 is satisfied and the angle between the liquid crystal molecules on the upper substrate and the liquid crystal molecules on the lower substrate is larger than 225 °,
By satisfying the relational expression of | d / p | = -θ / 1000 + 0.76 ± 0.1, it was found that a better display was obtained.
[0032]
Also, in the eighth invention of the present application, the liquid crystal molecules on both the first and second substrates have a uniform orientation in a state of being inclined at a certain angle from the normal direction to the substrates, and When the angle between the liquid crystal molecules of the above and the orientation direction of the liquid crystal molecules on the lower substrate is θ (however, the counterclockwise direction as viewed from the molecules on the upper substrate is positive), 200 ° ≦ θ ≦ 250 ° And
0.1 ≦ | d / p | ≦ 0.5 and 600 nm ≦ Δnd ≦ 1200 nm. With such a structure of the liquid crystal layer, the driving margin is set to such an extent that the drive margin can be applied to the STN mode. It can be set to a value, and even in the STN method, good display by uniform black and white display is realized.
[0033]
Furthermore, the ninth invention of the present application uses a plurality of optical phase difference compensating plates, and at least one optical phase difference compensating plate among the plurality of optical phase difference compensating plates disposed on the second substrate. The refractive index of the plate is nx>nz> ny (x and y are one direction parallel to the panel surface orthogonal to each other, z is a direction perpendicular to the panel surface, and hereinafter referred to as a biaxial optical phase difference compensator). With respect to the display in the dark state, the viewing angle dependence of the tilt angle of the display surface from the normal direction is dramatically improved, and a good black display is realized.
[0034]
Furthermore, regarding the display in the bright state and the dark state, the viewing angle dependency on the inclination angle of the display surface from the normal direction is such that the tenth invention of the present application has a negative refractive index difference and a phase difference of 135 nm to 1200 nm. And an optical phase difference compensator having substantially the same product of the birefringence difference of the liquid crystal and the thickness of the liquid crystal layer, the second substrate, and the plurality of optical devices arranged on the second substrate. By arranging it between the phase difference compensating plate and the phase difference compensating plate, a greatly improved good black and white display is realized.
[0035]
Furthermore, in the present invention, the liquid crystal layer is formed by mixing a liquid crystal and a polymer precursor and curing and phase-separating with UV to form a liquid crystal / cured polymer composite layer, or When the liquid crystal and the UV-curable liquid crystal are compatible with each other, a liquid crystal phase is formed. When the liquid crystal and the UV-curable liquid crystal are cured and phase-separated by UV, a liquid crystal / cured polymer composite layer is formed. It is also possible to form a display device.
[0036]
Further, an eleventh invention of the present application is the reflective liquid crystal display device according to the second or third invention of the present application, wherein x in the panel surface is positive (positive to the right), vertical is y (positive in the upward), and the panel surface is When the vertical direction is defined as z (the direction from the lower substrate to the upper substrate is positive), and all the z components of the direction of the liquid crystal molecules are defined as positive, the upper and lower substrates in which the liquid crystal molecules on the substrate are obliquely aligned Is characterized in that the y component of the orientation of the liquid crystal molecules on the substrate is positive, which is a liquid crystal configuration taking into account the intensity distribution of ambient light, which is the only light source of the reflective liquid crystal display device. . That is, under actual usage conditions, the user himself blocks the ambient light, and the incident light mainly enters from the positive direction together with y and z. By applying to the configuration, it is possible to provide a good display to a user of the reflective liquid crystal display device.
[0037]
Further, a twelfth invention of the present application is directed to a reflection type liquid crystal display device in which a polarizing plate, a half-wave plate, and a quarter wavelength plate are arranged on a top substrate of the reflection type liquid crystal display device according to the second or third invention in this order. With respect to the setting of the direction θ2 of the slow axis of the quarter-wave plate and the direction θ3 of the slow axis of the half-wave plate, assuming that the direction counterclockwise with respect to the transmission axis of the polarizing plate is positive,
70 ° ≦ θ2 ≦ 80 ° and 10 ° ≦ θ3 ≦ 20 °
, The orientation processing direction θ1 of the substrate on the side on which the alignment processing is performed among the upper and lower substrates is set to −90 ° ≦ θ1 ≦ −60 °
By doing so, good display without coloring is realized not only for white display but also for gradation display.
[0038]
Further, a thirteenth invention of the present application is directed to a reflective liquid crystal display device in which a polarizing plate, a half-wave plate, and a quarter-wave plate are arranged in this order on an upper substrate of the reflective liquid crystal display device according to the second or third invention. With respect to the setting of the direction θ2 of the slow axis of the quarter-wave plate and the direction θ3 of the slow axis of the half-wave plate, assuming that the direction counterclockwise with respect to the transmission axis of the polarizing plate is positive,
10 ° ≦ θ2 ≦ 20 ° and 70 ° ≦ θ3 ≦ 80 °
, The orientation processing direction θ1 of the substrate on the side on which the orientation processing is performed among the upper and lower substrates is set to −60 ° ≦ θ1 ≦ 0 °
By doing so, good display without coloring is realized not only for white display but also for gradation display.
[0039]
Further, a fourteenth invention of the present application is directed to a reflection type liquid crystal display device in which a polarizing plate, a half-wave plate, and a quarter wavelength plate are arranged on the upper substrate of the reflection type liquid crystal display device according to the second or third invention in this order. With respect to the setting of the direction θ2 of the slow axis of the quarter-wave plate and the direction θ3 of the slow axis of the half-wave plate, assuming that the direction counterclockwise with respect to the transmission axis of the polarizing plate is positive,
−80 ° ≦ θ2 ≦ −70 ° and −20 ° ≦ θ3 ≦ −10 °
When the orientation treatment direction θ1 of the substrate on which the orientation treatment is performed is set to 30 ° ≦ θ1 ≦ 60 °
By doing so, good display without coloring is realized not only for white display but also for gradation display.
[0040]
Further, a fifteenth invention of the present application is a reflective liquid crystal display device in which a polarizing plate, a half-wave plate, and a quarter-wave plate are arranged in order from the top on the upper substrate of the reflective liquid crystal display device according to the second or third invention of the present application. With respect to the setting of the direction θ2 of the slow axis of the quarter-wave plate and the direction θ3 of the slow axis of the half-wave plate, assuming that the direction counterclockwise with respect to the transmission axis of the polarizing plate is positive,
−20 ° ≦ θ2 ≦ −10 ° and −80 ° ≦ θ3 ≦ −70 °
And the orientation processing direction θ1 of the substrate on the side on which the orientation processing is performed among the upper and lower substrates is 60 ° ≦ θ1 ≦ 90 °
By doing so, good display without coloring is realized not only for white display but also for gradation display. Here, θ1, θ2, and θ3 are expressed between −90 ° and 90 °, but needless to say, they may be defined between 0 ° and 180 ° because of the periodicity of 180 °.
[0041]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. ◆
As shown in FIG. 1, a liquid crystal display device according to the present invention is a reflective liquid crystal display device in which illumination light such as external light is incident on a liquid crystal layer 1 through a polarizing plate 10 and is observed from the side of the polarizing plate 10 on which illumination is incident. It is. By the polarizing plate 10, only the linearly polarized light component of a specific direction in the illumination light is selectively transmitted and incident. The polarization state of the incident linearly polarized light is changed by a plurality of optical phase difference compensating plates to be circularly polarized light. Optically arranged. The incident light that has entered the liquid crystal layer reaches the reflection plate by changing the polarization state of the liquid crystal layer arranged according to the applied voltage. The polarization state on the reflection plate is realized in different states depending on the liquid crystal orientation.
[0042]
In the dark state, when no voltage is applied, the retardation of the liquid crystal layer in the layer normal direction is almost 0, and a good black display is provided. In the bright state, good white display is realized when the polarization state of incident light on the reflector is linearly polarized. The structure of the liquid crystal layer 1 that provides the best white display, that is, the structure of the liquid crystal layer 1 that converts circularly polarized light into linearly polarized light over a wide wavelength range will be considered.
[0043]
The optical action exerted by the liquid crystal layer 1 includes, for example, Δnd and | d / p | (liquid crystal layer thickness d, liquid crystal layer pitch p) of the liquid crystal layer, the direction of liquid crystal molecules on the upper substrate, and the liquid crystal on the lower substrate. It depends on parameters such as the angle between the direction of the molecule and the applied voltage. Here, the relationship between Δnd of the liquid crystal layer, which is the former two parameter, and | d / p | is focused, and first, discussion will be made on the case where one of the upper and lower substrates is rubbed.
[0044]
FIGS. 14A and 14B show the results of calculating the polarization state of light on the reflector when circularly polarized light is incident on the liquid crystal layer 1 using Δnd and | d / p | of the liquid crystal layer as variables. FIGS. 14A and 14B show calculation results when a voltage of 3.5 V is applied to the liquid crystal layer and when a virtually infinite voltage is applied to the liquid crystal layer, respectively. The lower limit value of the voltage was estimated as the minimum value of the peak voltage, and a value of 3.5 V was adopted.
[0045]
In addition, the liquid crystal molecules on the substrate on which the rubbing treatment was performed were uniformly oriented at an angle of 3 degrees from the substrate normal. In the area blacked out in the graph, the incident circularly polarized light is almost linearly polarized on the reflector, that is, an area that provides a good white display. The condition for providing a good white display in a wide wavelength range is that a region filled with black in the graph is a vertically wide region. Taking the drive margin into consideration, it can be estimated that the region | d / p | is 0.14 or more and 0.42 or less, and Δnd is 135 nm or more and 650 nm or less. The same study is performed when the rubbing process is performed on both the upper and lower substrates.
[0046]
Next, when the rubbing process is performed on both the upper and lower substrates, the angles θ between the liquid crystal molecules on the upper substrate and the liquid crystal molecules on the lower substrate are 0, 45, 90, 135, 180, 225, 270, When the angle was set to 315 °, graphs in the same format as in FIG. 14 were created, and the numerical limits of Δnd and | d / p | were made so that the black-painted area became longer vertically, as in the above-described criteria. Among them, graphs when θ is 45 ° and 270 ° are shown as typical examples in FIGS. 20A and 20B, respectively. From this, it can be estimated that the region that provides a good white display is 200 nm or more and 650 nm or less with respect to Δnd, and 0 ° or more and 200 ° or less with respect to θ, and 250 ° or more and 360 ° or less.
[0047]
<< Embodiment 1 >>
With reference to FIG. 1, a first embodiment in which a rubbing process is performed on only one of the substrates sandwiching the liquid crystal layer to form a reflective liquid crystal display device will be described. After the rubbing treatment, the setting | d / p | of the natural pitch p of the liquid crystal and the thickness d of the liquid crystal layer is set to 0.33, Δnd of the liquid crystal layer is set to 350 nm, and the optical phase difference between 135 nm and 270 nm is set. An example in which compensating plates are used one by one is shown.
[0048]
FIG. 1 is a sectional view showing the configuration of the reflection type liquid crystal display device of the present embodiment. The liquid crystal layer 1 is sandwiched between a substrate 4 on which a vertical alignment film 2 subjected to tilt alignment processing is formed and a substrate 5 on which a vertical alignment film 3 not subjected to alignment processing is formed, for example, by a method such as rubbing alignment processing. The substrates 4 and 5 are provided with electrodes 6 and 7 for applying a voltage to the liquid crystal layer, respectively. The electrode 7 may also serve as a reflector. In addition, when the electrode 7 is provided with reflectivity, the electrode 7 may have a smooth uneven shape enough to maintain the polarization of the reflected light. As the smooth uneven shape, one having a different uneven period on the reflecting plate depending on the direction may be used. An active element or the like may be used as a means for applying a voltage to the electrode pair configured as described above, but it goes without saying that the driving method is not particularly limited in the present invention.
[0049]
Further, an optical phase difference compensating plate 8 and an optical phase difference compensating plate 9 were arranged on the observer side of the substrate 4, and a polarizing plate 10 was further arranged, thereby producing a reflection type liquid crystal display device shown in FIG. Here, aluminum was used as the electrode 7 on the substrate 5 to be a light-reflective electrode, and the electrode 7 had both functions of a reflective film and an electrode.
[0050]
The reflective liquid crystal display device in this embodiment was adjusted so that the liquid crystal layer thickness was 4.7 μm, and a polyimide-based vertical alignment film was used as the alignment film, and the tilt angle was formed by rubbing. The tilt angle from the normal direction is 2 degrees. In the present embodiment, the rubbing treatment is performed only on one of the substrates, but it has been confirmed that a uniform orientation can be obtained.
[0051]
The alignment film that can be used in the present invention is a film that can vertically align the liquid crystal molecules included in the liquid crystal layer with respect to the insulating substrate, that is, a vertical alignment film. Any known vertical alignment film can be used as long as it has the above properties. For example, a material having a structure in which a long-chain alkyl group is bonded to a polyimide skeleton is mentioned. Specifically, a polyimide resin such as JALS-203 (manufactured by Nippon Synthetic Rubber Co., Ltd.) or SE-7511L (manufactured by Nissan Chemical Industries, Ltd.) is used. No.
[0052]
The thickness of the alignment film is about 0.05 to 0.1 μm. As a method for forming the alignment film, for example, a method in which a solution in which a polymer is dissolved is applied by a spinner coating method, a dip coating method, a screen printing method, a roll printing method, or the like, and dried, can be used. Further, a method in which a polymer precursor solution is applied by the same method as described above and cured under predetermined curing conditions (heating, light irradiation, etc.) can be used. Further, it can be formed by the Langmuir-Blodgett method.
[0053]
Needless to say, the liquid crystal that can be used in the liquid crystal layer of the present invention is not particularly limited as long as it is a nematic liquid crystal having negative dielectric anisotropy (n-type). For example, ZLI-2857, ZLI-4788, ZLI-4788-000 (manufactured by Merck Japan Ltd.) and the like can be mentioned. Further, the thickness of the liquid crystal layer is preferably 3 to 12 μm. The desired value can be adjusted by adding a chiral agent to the liquid crystal. As the chiral agent, any known one can be used, and examples thereof include S-811 (manufactured by Merck Japan) and cholesteryl nanoate.
[0054]
When the operating temperature range of the liquid crystal display device is wide, a chiral agent having a helical twisting power whose temperature dependence is opposite to that of the temperature may be used. Examples of such a chiral agent include S-1011 (manufactured by Merck Japan). ◆
In the present embodiment, ZLI-2857 manufactured by Merck having negative dielectric anisotropy was used as a liquid crystal material, and S-811 manufactured by Merck was added as a chiral agent. Δn of ZLI-2857 is 0.074, and in the present embodiment, the liquid crystal layer thickness is set to 4.7 μm, so that Δnd is set to 350 nm.
[0055]
As shown in FIG. 2, the specific settings are the transmission azimuth of the polarizing plate 10, 13 is the slow axis of the first optical phase difference compensator 8, and 14 is the second optical phase difference. This is the slow axis of the compensator 9. The angle between the transmission axis of the polarizing plate 12 and the slow axis of the first optical phase difference compensating plate 8 is θ2, and the angle between the transmission axis of the polarizing plate 12 and the slow axis of the second optical phase difference compensating plate 9 is formed. When the angle is θ3, the magnitudes of θ2 and θ3 are 15 ° and 75 °, respectively. Reference numeral 16 denotes the orientation of the liquid crystal on the vertical alignment film 2 formed on the substrate 4 when observed from the orientation of the incident light of the reflection type liquid crystal display device.
[0056]
In this embodiment, the angle between the liquid crystal molecules on the incident side and the polarizing plate is set to 30 °. However, since circularly polarized light is incident on the liquid crystal layer, the angle between the liquid crystal molecules on the incident side and the polarizing plate is basically Characteristics do not depend. Furthermore, since the value of | d / p |, which is the ratio of the pitch p of the liquid crystal to the thickness d of the liquid crystal layer, is set to 0.33, the liquid crystal molecules are vertically aligned without twisting in the initial state.
[0057]
The optical phase difference compensating plates 8 and 9 are both made of a stretched film made of polycarbonate, and the optical phase difference compensating plate 8 has a phase difference controlled from 130 nm to 140 nm with respect to transmitted light in the surface normal direction at a wavelength of 550 nm. The optical phase difference compensator 9 has a phase difference controlled from 265 nm to 275 nm for the same light. The arrangement of these optical phase difference compensating plates is an arrangement for improving the optical characteristics with respect to the front direction of the reflection type liquid crystal display device after fabrication, but in consideration of the characteristics by observing from the tilt direction together with the liquid crystal layer. Design changes are also possible.
[0058]
The design for changing the phase difference of the optical phase difference compensating plate with respect to the transmitted light in the inclined direction while satisfying the set angle condition of the present embodiment shown in FIG. It is possible to change one to a biaxial optical phase difference compensator.
[0059]
FIG. 3 is a graph showing the voltage dependence of the reflectance of the reflective liquid crystal display device thus manufactured. In order to measure the reflectance, as shown in FIG. 4, a means for applying a voltage to the reflection type liquid crystal display device of the present embodiment is driven, and light from the illumination light source device is transmitted from the substrate 4 side via a half mirror. The light is incident, and the reflected light from the light reflecting film on the substrate 5 is detected by a photodetector. In FIG. 3, a reflectance of 100% was obtained by using the same reflection type liquid crystal display device as in the present embodiment except that only a polarizing plate similar to the device to be measured was used without using an optical phase difference compensator. Is the reflectivity of the device. The luminosity factor (Y value) was used as the reflectance.
[0060]
From the results shown in FIG. 3, it is understood that good display characteristics with a brightness of 90% and a contrast of 40 were obtained at a driving voltage of 3 V or less. Each curve in FIG. 3 shows the dependence of the voltage-reflectance characteristic on the amount of chiral additive, that is, the amount of twist. | D / p | 0.33, 0 and 0.5. The curve 3-1 shows that a flat voltage-reflectance characteristic in which the reflectance does not attenuate on the higher voltage side than the peak voltage can be obtained. Curve 3-2 shows a graph of a voltage-reflectance characteristic when a liquid crystal having the same setting as that of the curve 3-1 is used except that no chiral agent is added.
[0061]
FIGS. 19 (a) and 19 (b) show that when Δnd is fixed to 350 nm and 200 nm, respectively, of the parameters of the liquid crystal layer and 360 | d / p | is changed, circularly polarized light having a wavelength of 550 nm is linearly polarized in the liquid crystal layer. Is expressed in a contour line display. The region painted black is a region where circularly polarized light is efficiently converted into linearly polarized light, that is, a region that provides white display on the panel. The graph format is obtained by replacing Δnd on the vertical axis of the graph of FIG. 14 with a voltage. As in the case of FIG. 14, the area painted black in FIG. 17 is a cell configuration condition that gives a good light state. The longer the region painted in black vertically, the flatter the voltage-reflectance characteristics in which the reflectivity does not attenuate on the higher voltage side than the peak voltage, and a wider drive margin can be obtained, which is a preferable cell in design. It is a configuration condition.
[0062]
In FIG. 19 (a), the region which is long and is painted black (independent of voltage) has 360 | d / p | within the range of 80 to 150, that is, gives a good white display | d / p | ranges from 0.22 to 0.42. Similar graphs were created and examined for Δnd having a size different from Δnd used in FIGS. 19 (a) and (b). As a result, the vertical direction within the claim range of Δnd and | d / p | It has been found that the cell configuration condition in which a long black region exists is when the range of Δnd is 200 nm to 650 nm and the range of | d / p | is 0.22 to 0.42.
[0063]
From these graphs, it was found that by adding the chiral agent, a voltage-reflectance characteristic in which the reflectance did not attenuate on the higher voltage side than the peak voltage was obtained, and the setting margin of the peak voltage could be widened. Further, it is possible to cope with a phenomenon in which the peak voltage shifts when the observation azimuth is changed in the azimuth direction with respect to the substrate normal. Furthermore, when the wavelength dependence of the reflectance was measured, almost flat characteristics were obtained, and good black-and-white display characteristics without coloring were obtained.
[0064]
Here, with the same arrangement configuration of the liquid crystal cell as in the above embodiment, by setting only the cell thickness to 4.7 μm and 3.1 μm, Δnd of the liquid crystal layer is set to 350 nm and 230 nm, and | d / p | The measurement of the viewing angle dependence at 33 and 0.22 was also performed. The incident light is projected from a direction inclined by 30 ° from the normal of the display surface, and the ratio of the white display to the black display when received in the front direction, that is, the contrast is measured from the 3 o'clock direction to the 12 o'clock direction. As shown in FIG. Curve 1 shows Δnd of the liquid crystal layer of 350 nm, and curve 2 shows Δnd of 230 nm.
[0065]
As is clear from FIG. 15, it was found that by setting Δnd to 230 nm, a contrast of 20 or more could be secured in almost all directions, and extremely excellent monochrome display was possible. Expressing the average value of the contrast in the azimuthal direction, it was 15 when Δnd was 350 nm, and 28 when Δnd was 230 nm. Therefore, within the claimed range of Δnd in claim 1, the range of Δnd that achieves a good viewing angle characteristic in which the average value of the contrast in the azimuthal direction is 15 or more was 135 nm to 350 nm.
[0066]
As for | d / p |, as a result of the study in FIG. 19, the range of | d / p | for realizing good display within the above-mentioned range of Δnd was from 0.14 to 0.34. By using a color filter substrate as the upper substrate 4, full-color display is also possible. It was also confirmed that more favorable viewing angle characteristics could be obtained by using both the biaxial optical retardation compensator and the optical retardation compensator having negative refractive index anisotropy.
[0067]
Further, in the same arrangement as in the first embodiment, the configuration of the liquid crystal layer is also the same, and while maintaining the configurations of the polarizing plate and the optical phase difference compensating plate disposed on the upper substrate 4, the transmission axis of the polarizing plate 10 The viewing angle dependence of the contrast of the reflective liquid crystal display device with respect to the angle between the directions of the liquid crystal molecules on the upper substrate 4 was calculated. FIGS. 16A and 16B show the results when the angle between the transmission axis of the polarizing plate and the direction of the liquid crystal molecules on the upper substrate 4 is 45 ° and 150 °. Here, the contrast is calculated by specular reflection, that is, the arrangement is such that the inclination angles of the light projecting axis and the light receiving axis are the same and the azimuth angles are different by 180 °. The diameter of the concentric circle indicates the inclination angle from the normal line of the display surface, and the azimuth of the concentric circle indicates the azimuth angle of the display surface.
[0068]
According to the result of FIG. 16A, in this configuration, particularly excellent contrast is provided in the azimuth of 120 ° to 300 °, and from the result of FIG. It was found to give angular properties.
[0069]
17 (a), 17 (b), 18 (a) and 18 (b), the angle between the transmission axis of the polarizing plate 10 and the direction of the liquid crystal molecules on the upper substrate 4 is shown. Similar calculations were performed with 0 °, 90 °, 135 °, and 165 °. As a result, it has been found that, in the configuration according to the third aspect, a viewing angle characteristic that is almost isotropic with respect to contrast can be obtained, and in the configuration according to the fourth aspect, a specific direction with particularly excellent contrast can be obtained. .
[0070]
<< Embodiment 2 >>
Next, a description will be given of a second embodiment in which a rubbing process is performed on both the upper and lower substrates sandwiching the liquid crystal layer to constitute a reflection type liquid crystal display device with reference to the drawings. After the rubbing process was performed on both the upper and lower substrates, the angle formed by the orientation processing direction of the substrates was 270 °, the Δnd of the liquid crystal layer was 300 nm, and three optical phase difference compensators (135 nm, 270 nm, and 270 nm) were used. The reflection type liquid crystal display device shown was manufactured.
[0071]
The electrode 7 on the substrate 5 was a light reflective electrode using aluminum. The liquid crystal layer is adjusted so that the thickness of the liquid crystal layer becomes 4.5 μm after the introduction of the liquid crystal, the angle between the alignment processing directions of the upper and lower substrates is set to 270 °, and the liquid crystal is a liquid crystal used in a normal TFT transmission type liquid crystal display. It has the same liquid crystal properties (dielectric anisotropy, elasticity, viscosity, temperature characteristics, and voltage holding characteristics) as those described above, and only Δε is adjusted to −3.0. The product of the liquid crystal layer thickness and the amount of birefringence is used. Was set to be 300 nm, and a chiral agent was added to make | d / p | of the liquid crystal 0.5.
[0072]
As shown in FIG. 6, the specific angle setting of the optical phase difference compensator is, as shown in FIG. 6, 12 a transmission azimuth of the polarizing plate 10, and a retardation of the first optical phase compensator 8. The directions of the axis, the slow axis of the second optical phase difference compensator 9 and the slow axis of the second optical phase difference compensator 11 are 13, 14 and 15, respectively. The angle between the transmission axis of the polarizing plate 12 and the slow axis of the first optical phase difference compensating plate 8 is θ2, and the angle between the transmission axis of the polarizing plate 12 and the slow axis of the first optical phase difference compensating plate 9 is formed. When the angle is θ3 and the angle between the transmission axis of the polarizing plate 12 and the slow axis of the first optical phase difference compensator 11 is θ4, the magnitudes of θ2, θ3, and θ4 are 7, 34, and 100, respectively. °. Reference numerals 16 and 17 denote the orientation of the liquid crystal on the vertical alignment film 2 formed on the substrate 4 and the vertical alignment film formed on the substrate 5, respectively, when observed from the direction of the incident light of the reflection type liquid crystal display device. 3 is the orientation direction of the liquid crystal on 3.
[0073]
Each of these three optical retardation compensating plates is made of a uniaxial stretched film made of polycarbonate, and the optical retardation compensating plate 8 is controlled from 130 nm to 140 nm for transmitted light in the surface normal direction at a wavelength of 550 nm. The optical phase difference compensators 9 and 11 have a phase difference controlled from 265 nm to 275 nm for similar light. The polarizing plate 10 is a polarizing plate having an AR (Anti-Reflective) layer made of a dielectric multilayer film and having a single-unit internal transmittance of 45%.
[0074]
The reflectance of the reflective liquid crystal display device thus manufactured was measured in the arrangement shown in FIG. 4 similarly to that of the first embodiment, and 100% was the same as that of the first embodiment.
[0075]
The voltage-reflectance characteristic of the liquid crystal display element of Embodiment 2 manufactured as described above is shown by a curve 7-1 in FIG. 7, and as a comparative example, the voltage when | d / p | is 0 and 0.67 -The reflectance characteristics are shown in curves 7-2 and 7-3, respectively. According to this result, according to the result, it was found from the comparison between the curves 7-1 and 2 that the reflectance of the curve 7-1 to which the chiral agent was added was not attenuated on the higher voltage side than the peak voltage. From this, it was found that the driving margin could be widened.
[0076]
Further, the characteristic that the reflectance is not attenuated on the higher voltage side than the peak voltage can cope with the phenomenon that the peak voltage shifts when the observation direction is changed in the azimuth direction with respect to the substrate normal. . There is an optimal condition for the amount of the chiral agent that gives good voltage-reflectance characteristics, and if the amount is too large, good voltage-reflectance characteristics may not be obtained as shown by the curve 7-3. Do you get it. Further, when the wavelength dependence of the reflectance was measured, it was found that the conditions under which substantially flat characteristics were obtained and the optimum conditions for the amount of the chiral agent added were in agreement.
[0077]
The brightness in the bright state was 95%, and the contrast ratio was 20. As a result, it has been found that a sufficient reflectance in a bright state and a sufficient contrast ratio are realized, and the reflection type liquid crystal display device is excellent even in visual observation. The contrast ratio was defined by dividing the reflectance in the bright state (the applied voltage was the voltage having the highest reflectance in each example) by the reflectance in the dark state. As the applied voltage in the bright state, the voltage having the highest reflectance was used for each example, and in the dark state, the voltage was applied without voltage. That is, it has been confirmed that the contrast is improved in the reflective liquid crystal display device in which circularly polarized light is produced by using three optical retardation compensators.
[0078]
In this embodiment, a chiral agent that makes | d / p | of the liquid crystal layer 0.5 is added. With this setting, the liquid crystal layer is twisted by 180 °. As a result, the liquid crystal layer and the interface do not match.
[0079]
However, the present inventors have found that by applying | d / p | and the angle between the alignment directions of the liquid crystal molecules on the upper and lower substrates, the characteristics are better than the condition where the interface with the liquid crystal layer is matched. I have. FIG. 8 shows the relationship between the rubbing angle and the optimum condition of | d / p |. That is, as shown in FIG. 8, the angle formed between the liquid crystal molecules on the upper substrate and the liquid crystal molecules on the lower substrate and the optimum condition of | d / p | are shown.
[0080]
That is, the hatched portion in FIG. 8 indicates the range of the optimum condition of the amount of the chiral agent to be added which gives a good voltage-reflectance characteristic with respect to the angle formed by the liquid crystal molecules on the upper substrate and the lower substrate. The present inventors have confirmed from both the computer simulation and the experiment that good display is provided under the optimum conditions defined by FIG. In the case of the present embodiment, since the angle formed between the liquid crystal molecules on the upper substrate and the liquid crystal molecules on the lower substrate is 270 °, the optimum | d / p | may be 0.4 or more and 0.6 or less. Understand.
[0081]
<< Embodiment 3 >>
Further, rubbing treatment is performed on the upper and lower substrates so that the angle between the alignment processing directions of the upper and lower substrates becomes 225 ° (so-called STN), the Δnd of the liquid crystal layer is set to 940 nm, and one optical phase difference compensator of 135 nm and 270 nm is provided. The chiral pitch was adjusted to 13.5 μm by adding CN (cholesteryl nanoate) as a chiral agent to ZLI4850 (Δn: 0.208, manufactured by Merck Japan) which is a nematic liquid crystal having a negative dielectric anisotropy. Then, it was sandwiched as a liquid crystal layer having a liquid crystal layer thickness of 4.5 μm. Here, | d / p | of the liquid crystal is set to 0.33, and since the angle between the alignment processing directions of the upper and lower substrates is 225 °, this is also due to the twist of the liquid crystal layer and the regulating force of the upper and lower substrates. Is not consistent with
[0082]
On the substrate 4 of the liquid crystal cell thus manufactured, two optical retardation compensating plates and a polarizing plate similar to those shown in FIG. 2 were arranged, and a reflective liquid crystal display device of the third embodiment was manufactured. . ◆
When this reflection type liquid crystal display device was driven in a simple matrix at a duty of 1/240, a display having a good contrast of 10 was obtained.
[0083]
FIG. 9 shows measurement results of the voltage-reflectance characteristics of the reflective liquid crystal display device according to the third embodiment. The reflectivity in FIG. 9 is measured in the arrangement shown in FIG. 4 as in the first embodiment, and 100% is the same as in the first embodiment.
[0084]
In addition, the steepness of the electro-optical characteristics when Δnd of the liquid crystal layer and the angle θ between the alignment directions of the upper and lower substrates are changed, without being limited to the present embodiment, was examined. Typical examples are shown in FIGS. 21 (a) and 21 (b) and FIGS. 22 (a) and 22 (b). From the above, it was confirmed that in the region where Δnd is from 600 nm to 1200 nm and | d / p | is 0.1 or more and 0.5 or less, the steepness of electro-optical characteristics is high and simple matrix driving is possible.
[0085]
<< Embodiment 4 >>
In the above embodiment, a uniaxial stretched film is used as the optical retardation compensating plate. However, biaxiality, that is, biaxiality produced from a retardation compensating plate capable of controlling the refractive index three-dimensionally or a liquid crystal polymer. FIG. 10 shows a structure of a reflection type liquid crystal display device using an optical phase difference compensator with an optical phase difference compensator having a negative refractive index anisotropy. Here, FIG. 10 shows the relationship between the second substrate 4 and the optical phase difference compensating plate 8 arranged on the second substrate 3 in the reflection type liquid crystal display device having the structure shown in FIG. The optical phase difference compensating plate 29 having a negative refractive index anisotropy is inserted into the optical disc. Here, the retardation of the optical phase difference compensating plate 29 in the normal direction of the plate surface is set to be substantially the same value as Δnd of the liquid crystal layer 1 and formed on the first substrate 5. The reflective electrode 7 has a concave-convex shape having in-plane anisotropy.
[0086]
FIG. 11 shows the viewing angle dependence of the luminance of the display surface of the reflective liquid crystal display device thus manufactured when no voltage is applied, that is, in a dark state. Here, the reflection luminance is calculated in the arrangement of regular reflection, that is, the inclination angles of the light projecting axis and the light receiving axis are the same, and the azimuth angles are different by 180 °. The diameter of the concentric circle indicates the inclination angle from the normal line of the display surface, and the azimuth of the concentric circle indicates the azimuth angle of the display surface. In addition, FIG. 11A shows the result when a uniaxial optical phase difference compensator is used as the optical phase difference compensator, and FIG. 11B shows the result when a biaxial optical phase difference compensator is used. From these results, the region where a good dark state with a reflection luminance of 0.04 or less is reproduced is a region where the tilt angle is about 0 ° or more and 40 ° or less when a uniaxial optical phase difference compensator is used. On the other hand, when the biaxial optical phase difference compensating plate is used, the viewing angle becomes almost the entire region, the tilt angle is 0 ° or more and 80 ° or more, and the viewing angle characteristic is greatly improved by using the biaxial optical phase difference compensating plate. It was found to improve.
[0087]
<< Embodiment 5 >>
Further, as a fifth embodiment, with the same arrangement as in the fourth embodiment, illumination light is incident from a direction inclined by 30 ° from the normal of the display surface, and the ratio of white display to black display when observed in the front direction. That is, the contrast was measured from the 3 o'clock direction to the 9 o'clock direction from the 12 o'clock direction. FIG. 12 shows the measurement results.
[0088]
As is clear from the figure, a contrast of 20 or more can be guaranteed in almost all directions, and very excellent monochrome display is possible. By using a color filter substrate as the upper substrate 4, full-color display is possible.
[0089]
In the present embodiment, both the biaxial optical retardation compensator and the optical retardation compensator having a negative refractive index anisotropy are used, but the optical retardation compensator having a negative refractive index anisotropy is used. In addition, it has been confirmed that even when only the biaxial optical phase difference compensator is used, better display characteristics can be obtained than when only the uniaxial optical phase compensator is used.
[0090]
<< Embodiment 6 >>
A sixth embodiment in which a polymer precursor is added as the liquid crystal layer in the first embodiment will be described. As shown in FIG. 13, the configuration of the reflection type liquid crystal display device is almost the same as that of the first embodiment, and a liquid crystal / polymer composite layer 30 is sandwiched between two transparent substrates 4 and 5, The liquid crystal / polymer composite layer 30 is in a state where the liquid crystal 1 is phase-separated in the matrix of the cured polymer 31. The liquid crystal / polymer composite layer 30 exists as a continuous body.
[0091]
The polymer is mixed with a liquid crystal and a polymerization initiator as a polymer precursor, cured by irradiating with ultraviolet light (hereinafter referred to as UV light), and used as a polymer to phase-separate from the liquid crystal 1 when becoming a polymer. Is done. As the liquid crystal 1, a liquid crystal having a negative dielectric anisotropy oriented in a direction parallel to the electric field direction is used. Hereinafter, the polymer after UV irradiation is referred to as a cured polymer. Each of the two substrates 4 and 5 has a transparent electrode 6 and a reflective electrode 7 on the inner surface, respectively, and further has vertical alignment films 2 and 3 formed thereon. A flat mirror having specularity was used as the reflective electrode.
[0092]
The vertical alignment films 2 and 3 are subjected to an alignment process for aligning the liquid crystal 1 having a negative dielectric anisotropy sandwiched between two substrates in a direction perpendicular to the substrates 4 and 5. Since the cured polymer 31 is cured by a photopolymerization reaction, it is immobilized and cannot respond to an electric field. Further, since the liquid crystal 1 is not fixed in the alignment state, when the electric field is applied, the liquid crystal 1 is aligned in the direction of the electric field.
[0093]
Therefore, when no electric field is applied, the orientation direction of the liquid crystal 1 is in a state of being coincident with the direction perpendicular to the substrates 4 and 5. In this state, the refractive index of the liquid crystal with respect to ordinary light and the refractive index of the polymer are different. Are matched, the liquid crystal cell becomes transparent. Therefore, good black display can be realized as in the first embodiment.
[0094]
When a power supply is connected between the transparent electrode 6 and the reflective electrode 7 and an electric field is applied to the liquid crystal / polymer composite layer 30, the orientation of the liquid crystal 1 is changed to the direction of the electric field due to the effect of the chiral substance added to the liquid crystal. To align. When the liquid crystal 1 is twisted at a predetermined angle and becomes in a light scattering state at the interface between the liquid crystal 1 and the cured polymer 31 due to a mismatch in refractive index, the liquid crystal cell becomes cloudy. In addition, even when a mirror surface is used as the reflective electrode, the surface becomes white due to scattering of the liquid crystal layer.
[0095]
As the cured polymer 31, any polymer that mixes with a liquid crystal, is sealed in two substrates 4 and 5, is polymerized after UV irradiation, and forms a matrix by phase separation with the liquid crystal is applicable to the present invention. It goes without saying that it is possible. Needless to say, UV-curable liquid crystals that exhibit liquid crystallinity in the state of a polymer precursor are also applicable to the present invention. In this case, the UV cure liquid crystal is also vertically aligned. In the present embodiment, a mirror-like reflective electrode is used. However, even if a concave-convex reflective electrode is used, scattering can be further increased, and good display without reflection can be realized.
[0096]
<< Embodiment 7 >>
Further, as the seventh embodiment, the same arrangement as in the first embodiment is used, and the liquid crystal layer is configured so that Δnd is 230 nm and | d / p | is 0.25, and the optical phase difference compensation between 135 nm and 270 nm is performed. An example of a reflection type liquid crystal display device using one plate at a time will be described. As a specific setting, as shown in FIG. 2, the counterclockwise direction with respect to the transmission direction 12 of the polarizing plate 10 is set to be positive, the rubbing direction 16 of the upper substrate is set to θ1, and the first optical phase difference compensating plate is set. 8, the azimuth 13 of the slow axis is θ2, the azimuth 14 of the slow axis of the second optical phase difference compensating plate 9 is θ3, and the θ1 is -45 °, 0 °, 45 °, and 90 °. , Θ2 and θ3, as combinations of (θ2, θ3), (15 °, 75 °), (75 °, 15 °), (−15 °, −75 °), (−75 °, −15 °) And 16 combinations were used.
[0097]
Regarding the viewing angle characteristics of the reflection type liquid crystal display device used in this embodiment, the illumination light is incident from a direction inclined by 30 ° from the normal of the display surface, the ratio of white display to black display when observed in the front direction, That is, the contrast ratio was measured by changing the incident azimuth by 360 ° every three degrees. The measurement results when the combination of (θ2, θ3) is (15 °, 75 °), (75 °, 15 °), (-15 °, -75 °), (-75, -15 °) 23 (a), 23 (b), 24 (a) and 24 (b). The vertical axis indicates the contrast ratio, which was obtained by dividing the reflectance of white display when the applied voltage was 4.5 V by the reflectance of black display when the applied voltage was 1.5 V. The horizontal axis indicates the incident azimuth of the incident light. Here, the direction of the incident azimuth of 0 ° is aligned with the orientation direction of the liquid crystal molecules on the upper substrate.
[0098]
From both graphs of FIGS. 23 and 24, the incident light azimuth where the contrast ratio is low is from 90 ° to 270 °, and by using a configuration in which the panel user is arranged within this range. That is, by setting the vertical component in the panel plane of the orientation direction of the liquid crystal molecules on the upper substrate to face upward, a good contrast ratio can be realized in an actual use environment. ◆
In this embodiment, the case where only the upper substrate is subjected to the rubbing treatment is shown, but the same result is obtained when only the lower substrate is subjected to the rubbing treatment.
[0099]
<< Embodiment 8 >>
Further, as the eighth embodiment, the same settings as those of the seventh embodiment are set regarding the combination of the setting of the liquid crystal layer, the transmission axis of the polarizing plate, the slow axis of the optical phase difference compensator, and the direction of the rubbing process performed on the upper substrate. The chromaticity of gradation display when observed in the front direction under diffused light was measured. Here, gradation display was performed by changing the voltage from 0 V to 5 V every 0.5 V.
[0100]
Therefore, when the combination of (θ2, θ3) is (15 °, 75 °), (75 °, 15 °), (−15 °, −75 °), (−75 °, −15 °) The results are displayed as L * a * b * and are shown in FIGS. 25 (a), 25 (b), 26 (a) and 26 (b), respectively. Each graph shows the angle of the slow axis of the first optical phase difference compensator 8 and the angle of the slow axis of the second optical phase difference compensator 9 with reference to the direction of the transmission axis of the polarizing plate. Are the results when (15 °, 75 °), (75 °, 15 °), (−15 °, −75 °), (−75 °, −15 °), respectively. From both graphs, it can be seen that when the applied voltage is low, the color becomes bluish, and as the applied voltage increases, the color changes from green to yellow.
[0101]
Here, the following evaluation function formula 1 proposed in recent years is used as the evaluation function of whiteness. This evaluation function indicates that the larger the evaluation value W is, the more the whiteness is felt, and the smaller the evaluation value W, the more the color is felt.
[0102]
(Equation 1)

FIG. 25 (a), FIG. 25 (b), FIG. 26 (a), and FIG. 26 (a), in which the above evaluation function is applied, the vertical axis represents the evaluation value W, and the horizontal axis represents the applied voltage. 27 (a), 27 (b), 28 (a), and 28 (b), respectively. When a range of θ1 in which the evaluation value W becomes large is obtained from this graph, the optimum θ1 as shown in Table 1 could be obtained, although it differs depending on the combination of (θ2, θ3). The range of the optimum θ1 also matched the result of the visual observation.
[0103]
[Table 1]

In this example, the case where the rubbing treatment was performed only on the upper substrate was shown, but the same result was obtained when the rubbing treatment was performed only on the lower substrate.
[0104]
Further, in the present embodiment, the setting range of the slow axis of the optical phase difference compensating plate has a width of 10 °, but within this range, actual observation was made, and it was confirmed that the above result was maintained. ing. Regarding the type of the optical retardation compensator, it has been confirmed that the above result is maintained regardless of the difference between the uniaxial retarder or the biaxial retarder and the use of the negative retarder.
[0105]
【The invention's effect】
As is clear from the above description, the reflection type liquid crystal display device according to the present invention can realize a reflection type liquid crystal display device having high reflectance and high contrast. Further, the reflection film forming surface of the reflection plate can be provided on the liquid crystal layer side of the transparent substrate, and a good dark state can be realized. Therefore, a moving image can be displayed with high contrast and high definition without parallax. Since the liquid crystal layer is twisted, the viewing angle characteristics are excellent. Further, if a color filter adjusted to high brightness is used in the present device, a color reflective liquid crystal display device having good display quality and high color reproducibility can be realized.
[Brief description of the drawings]
FIG. 1 is a structural cross-sectional view of a reflective liquid crystal display device when two optical phase difference compensators are used.
FIG. 2 is a plan view showing the setting directions of a polarizing plate and an optical phase difference compensator when two optical phase difference compensators are used.
FIG. 3 is a diagram illustrating a relationship between a reflectance and an applied voltage in the reflective liquid crystal display device according to the first embodiment.
FIG. 4 is an arrangement diagram of an optical system at the time of measuring reflectance in the reflective liquid crystal display device of the embodiment.
FIG. 5 is a structural sectional view of a reflection type liquid crystal display device when three optical phase difference compensators are used.
FIG. 6 is a plan view showing setting directions of a polarizing plate and an optical phase difference compensator when three optical phase difference compensators are used.
FIG. 7 is a relationship diagram between a reflectance and an applied voltage in the reflection type liquid crystal display device of the second embodiment.
FIG. 8 is a diagram showing the relationship between the angle formed by the liquid crystal molecules on the upper substrate and the liquid crystal molecules on the lower substrate and the optimal condition of | d / p | in the reflective liquid crystal display device of Embodiment 2.
FIG. 9 is a diagram illustrating a relationship between a reflectance and an applied voltage in the reflective liquid crystal display device according to the third embodiment.
FIG. 10 is a structural sectional view of a reflective liquid crystal display device according to a fifth embodiment.
FIGS. 11A and 11B show a case where a uniaxial optical phase difference compensating plate is used, and FIG. 11B shows a case where a biaxial optical phase difference compensating plate is used. FIG. 7 is a diagram illustrating the relationship between the luminance of the display surface and the azimuth of the display surface in an added state.
FIG. 12 is a diagram showing the relationship between the contrast and the azimuth of the display surface in the reflective liquid crystal display device of the fifth embodiment.
FIG. 13 is a structural sectional view of a reflective liquid crystal display device according to a sixth embodiment.
FIG. 14 is a diagram showing the relationship between Δnd and 360 × | d / p | when the voltage is 3.5 V (a) based on the evaluation function and the voltage is virtually infinite (b).
FIG. 15 is an explanatory diagram of the incident light azimuth dependence of the contrast in the reflective liquid crystal display device of the first embodiment.
FIG. 16 shows reflection when the angle between the transmission axis of the polarizing plate 10 and the direction of the liquid crystal molecules on the upper substrate 4 is 45 ° (a) or 150 ° (b) in the reflective liquid crystal display device of the first embodiment. FIG. 4 is a contour diagram of luminance.
FIG. 17 shows reflection when the angle between the transmission axis of the polarizing plate 10 and the direction of the liquid crystal molecules on the upper substrate 4 is 0 ° (a) or 90 ° (b) in the reflective liquid crystal display device of the first embodiment. FIG. 4 is a contour diagram of luminance.
FIG. 18 shows the reflection when the angle between the transmission axis of the polarizing plate 10 and the direction of the liquid crystal molecules on the upper substrate 4 is 135 ° (a) and 165 ° (b) in the reflective liquid crystal display device of the first embodiment. FIG. 4 is a contour diagram of luminance.
FIGS. 19A and 19B show, in the reflection type liquid crystal display device of the first embodiment, (a) the applied voltage by the evaluation function and 360 | d when the Δnd of the liquid crystal layer is 350 nm and the Δnd of the liquid crystal layer is 200 nm. / P | is a relationship diagram.
FIG. 20 shows Δnd and 360 | by an evaluation function when the angle between the alignment direction of liquid crystal molecules on the upper substrate and the alignment direction of liquid crystal molecules on the lower substrate is (a) 45 ° and (b) 270 °. FIG. 4 is a relationship diagram of d / p |.
FIG. 21 is a view showing an example in which the angle between the alignment direction of the liquid crystal molecules on the upper substrate and the alignment direction of the liquid crystal molecules on the lower substrate is 225 ° in the reflective liquid crystal display device of Embodiment 3, and | d / p | FIG. 6 is a diagram showing the relationship between Δnd and applied voltage by an evaluation function when 0.1) and (b) 0.3.
FIG. 22 shows that, in the reflective liquid crystal display device of Embodiment 3, the angle between the alignment direction of the liquid crystal molecules on the upper substrate and the alignment direction of the liquid crystal molecules on the lower substrate is 225 °, and | d / p | FIG. 7 is a diagram showing the relationship between Δnd and applied voltage by an evaluation function when 0.5) and (b) 0.7.
FIG. 23 is a view showing the relationship between contrast and the incident azimuth of incident light in the reflective liquid crystal display device of Embodiment 7.
FIG. 24 is a diagram showing the relationship between contrast and the incident azimuth of incident light in the reflective liquid crystal display device of the seventh embodiment.
FIG. 25 is a diagram showing L * a * b * of chromaticity when gradation display is performed in the reflective liquid crystal display device of the eighth embodiment.
FIG. 26 is a diagram showing L * a * b * of chromaticity when gradation display is performed in the reflective liquid crystal display device of the eighth embodiment.
FIG. 27 is a diagram showing chromaticity when gradation display is performed in the reflection type liquid crystal display device of Embodiment 8 in a relationship between an evaluation function by Expression 1 and a voltage.
FIG. 28 is a diagram showing chromaticity when gradation display is performed in the reflection type liquid crystal display device of Embodiment 8 in the relationship between an evaluation function according to Equation 1 and voltage.
[Explanation of symbols]
1 Liquid crystal layer
2 Vertical alignment film
3 Vertical alignment film
4 Second substrate
5 First substrate
6 electrodes
7 reflective electrode
8 First optical phase difference compensator
9 Second optical phase difference compensator
10 Polarizing plate
11 Third optical phase difference compensator
12 Polarization plate transmission direction
13 Slow axis direction of the first optical phase difference compensator
14 Slow axis direction of the second optical phase difference compensator
15 Slow axis direction of the third optical phase difference compensator
16 Orientation of liquid crystal alignment on second substrate (alignment processing direction)
17 Orientation of liquid crystal alignment on first substrate (alignment processing direction)
18. Reflective liquid crystal display device according to Embodiment 3 of the present invention
29 Negative refractive index anisotropic optical phase difference compensator
30 Liquid crystal / polymer composite layer
31 Polymer

Claims (15)

A first substrate having a light-reflective electrode, a transparent second substrate having a transparent electrode, a negative dielectric anisotropy sandwiched between the first substrate and the second substrate, and voltage application A nematic liquid crystal layer that is twisted in accordance with the above, and a plurality of optical phase difference compensating plates and a single polarizing plate that are provided on the second substrate so that circularly polarized light is incident on the liquid crystal layer. Type liquid crystal display device,
Liquid crystal molecules on at least one of the first and second substrates have an angle of 0 ° or more and less than 10 ° from the normal direction of the substrate,
When the natural pitch of the liquid crystal is p, the liquid crystal layer thickness is d, and the birefringence difference of the liquid crystal is Δn,
The natural pitch of the liquid crystal, the liquid crystal layer thickness, and the birefringence difference of the liquid crystal are selected so that 0 <| d / p | ≦ 0.7 and 135 nm ≦ Δnd ≦ 1200 nm are satisfied .
The liquid crystal display device according to claim 1, wherein the liquid crystal layer is vertically aligned when no voltage is applied and twisted when a voltage is applied . A first substrate having a light-reflective electrode, a transparent second substrate having a transparent electrode, a negative dielectric anisotropy sandwiched between the first substrate and the second substrate, and voltage application A nematic liquid crystal layer that is twisted in accordance with the above, and a plurality of optical phase difference compensating plates and a single polarizing plate that are provided on the second substrate so that circularly polarized light is incident on the liquid crystal layer. Type liquid crystal display device,
Only the liquid crystal molecules on one of the first and second substrates have a uniform orientation in a state of being inclined at a certain angle from the normal direction of the substrate,
When the natural pitch of the liquid crystal is p, the liquid crystal layer thickness is d, and the birefringence difference of the liquid crystal is Δn,
The natural pitch of the liquid crystal, the liquid crystal layer thickness, and the birefringence difference of the liquid crystal are selected so that 0.22 ≦ | d / p | ≦ 0.42 and 200 nm ≦ Δnd ≦ 650 nm are satisfied .
The liquid crystal display device according to claim 1, wherein the liquid crystal layer is vertically aligned when no voltage is applied and twisted when a voltage is applied . A first substrate having a light-reflective electrode, a transparent second substrate having a transparent electrode, a negative dielectric anisotropy sandwiched between the first substrate and the second substrate, and voltage application A nematic liquid crystal layer that is twisted in accordance with the above, and a plurality of optical phase difference compensating plates and a single polarizing plate that are provided on the second substrate so that circularly polarized light is incident on the liquid crystal layer. Type liquid crystal display device,
Only the liquid crystal molecules on one of the first and second substrates have uniform orientation in a state of being inclined at a certain angle from the normal direction of the substrate, the natural pitch of the liquid crystal is p, and the liquid crystal layer thickness is Is d, and the birefringence difference of the liquid crystal is Δn,
The natural pitch of the liquid crystal, the liquid crystal layer thickness, and the birefringence difference of the liquid crystal are selected so that 0.14 ≦ | d / p | ≦ 0.34 and 135 nm ≦ Δnd ≦ 350 nm are satisfied .
The liquid crystal display device according to claim 1, wherein the liquid crystal layer is vertically aligned when no voltage is applied and twisted when a voltage is applied . 4. The reflection type liquid crystal display device according to claim 2, wherein an orientation direction of liquid crystal molecules on the first or second substrate and a direction of an absorption axis of a polarizing plate arranged on the first substrate are different. A reflection type liquid crystal display device, wherein 90 ° ≦ θ1 ≦ 165 ° when the angle formed is θ1. 4. The reflection type liquid crystal display device according to claim 2, wherein an orientation direction of liquid crystal molecules on the first or second substrate and a direction of an absorption axis of a polarizing plate arranged on the first substrate are different. A reflection type liquid crystal display device, characterized in that -15 ° ≦ θ1 ≦ 90 ° when the angle formed is θ1. 2. The reflective liquid crystal display device according to claim 1, wherein the liquid crystal molecules on both the first and second substrates have a uniform orientation in a state in which the liquid crystal molecules are inclined at a certain angle from a normal direction to the substrates. When the angle between the liquid crystal molecules on the upper substrate and the orientation direction of the liquid crystal molecules on the lower substrate is represented by θ (however, the counterclockwise direction as viewed from the molecules on the upper substrate is positive), 0 ° ≦ θ ≦ 200 ° or 250 ° ≦ θ ≦ 360 ° and 200 nm ≦ Δnd ≦ 650 nm. 7. The reflection type liquid crystal display device according to claim 6, wherein the value of | d / p | when the natural pitch of the liquid crystal is p and the thickness of the liquid crystal layer is d is the liquid crystal molecules on the upper substrate and the liquid crystal molecules on the lower substrate. Is smaller than 225 °, the relational expression | d / p | = −θ / 1000 + 0.40 ± 0.1 is satisfied, and the liquid crystal molecules on the upper substrate and the liquid crystal molecules on the lower substrate Is larger than 225 °, a relational expression of | d / p | = −θ / 1000 + 0.76 ± 0.1 is satisfied. 2. The reflective liquid crystal display device according to claim 1, wherein the liquid crystal molecules on both the first and second substrates have a uniform orientation in a state in which the liquid crystal molecules are inclined at a certain angle from a normal direction to the substrates. When the angle between the liquid crystal molecules on the upper substrate and the orientation direction of the liquid crystal molecules on the lower substrate is defined as θ (however, the counterclockwise direction viewed from the molecules on the upper substrate is defined as positive), 200 ° ≦ θ ≦ 250 °, 0.1 ≦ | d / p | ≦ 0.5 and 600 nm ≦ Δnd ≦ 1200 nm. 2. The reflective liquid crystal display device according to claim 1, wherein at least one of the plurality of optical retardation compensators disposed on the second substrate has a refractive index of nx> nx. A reflection type liquid crystal display device, wherein nz> ny (x and y are one direction parallel to the panel surface orthogonal to each other, and z is a direction perpendicular to the panel surface). 2. The reflection type liquid crystal display device according to claim 1, wherein the refractive index difference is negative, the phase difference is from 135 nm to 1200 nm, and the optical position is substantially the same as the product of the birefringence difference of the liquid crystal and the thickness of the liquid crystal layer. A reflection type liquid crystal display device, wherein a phase difference compensating plate is disposed between the second substrate and the plurality of optical phase difference compensating plates disposed on the second substrate. 4. The reflection type liquid crystal display device according to claim 2, wherein the horizontal direction in the panel surface is x (positive in the right direction), the vertical direction is y (positive in the upward direction), and the vertical direction in the panel surface is z (up from the lower substrate). When the substrate direction is defined as positive) and the z component of the direction of the liquid crystal molecules is defined as positive, the orientation of the liquid crystal molecules on the one of the upper and lower substrates on which the liquid crystal molecules on the substrate are tilted is aligned. A reflective liquid crystal display device, wherein the y component is positive. 4. A reflective liquid crystal display device according to claim 2, wherein a polarizing plate, a half-wave plate, and a quarter-wave plate are arranged on the upper substrate in this order from the transmission axis of the polarizing plate. Regarding the setting of the direction of the slow axis of the quarter-wave plate θ2 and the direction of the slow axis of the half-wave plate θ3 assuming the counterclockwise direction as positive, 70 ° ≦ θ2 ≦ 80 ° and 10 ° ≦ θ3 ≦ 20 °, when the counterclockwise direction is positive with respect to the transmission axis of the polarizing plate, the orientation processing direction θ1 of the substrate on the side of the upper and lower substrates on which the alignment process is performed is −90 ° ≦ θ1 ≦ −60 ° A reflective liquid crystal display device, characterized in that: 4. A reflective liquid crystal display device according to claim 2, wherein a polarizing plate, a half-wave plate, and a quarter-wave plate are arranged on the upper substrate in this order from the transmission axis of the polarizing plate. Regarding the setting of the direction of the slow axis of the quarter-wave plate θ2 and the direction of the slow axis of the half-wave plate θ3 assuming that the counterclockwise direction is positive, 10 ° ≦ θ2 ≦ 20 ° and 70 ° ≦ θ3 ≦ 80 °, when the counterclockwise direction is positive with respect to the transmission axis of the polarizing plate, the orientation processing direction θ1 of the substrate on the side of the upper and lower substrates on which the alignment process is performed is −60 ° ≦ θ1 ≦ 0 °. A reflective liquid crystal display device. 4. A reflective liquid crystal display device according to claim 2, wherein a polarizing plate, a half-wave plate, and a quarter-wave plate are arranged on the upper substrate in this order from the transmission axis of the polarizing plate. Regarding the setting of the direction θ2 of the slow axis of the quarter-wave plate and the direction θ3 of the slow axis of the half-wave plate, assuming that the counterclockwise direction is positive, −80 ° ≦ θ2 ≦ −70 ° and −20 ° ≦ When θ3 ≦ −10 °, the counterclockwise direction is defined as positive with respect to the transmission axis of the polarizing plate, and the orientation processing direction θ1 of the substrate on the side of the upper and lower substrates on which the alignment process is performed is 30 ° ≦ θ1 ≦ A reflection type liquid crystal display device characterized in that the angle is 60 °. 4. A reflective liquid crystal display device according to claim 2, wherein a polarizing plate, a half-wave plate, and a quarter-wave plate are arranged on the upper substrate in this order from the transmission axis of the polarizing plate. Regarding the setting of the direction θ2 of the slow axis of the quarter-wave plate and the direction θ3 of the slow axis of the half-wave plate, with the counterclockwise direction as positive, −20 ° ≦ θ2 ≦ −10 ° and −80 ° ≦ When θ3 ≦ −70 °, the counterclockwise direction with respect to the transmission axis of the polarizing plate is defined as positive, and the orientation direction θ1 of the substrate on the side of the upper and lower substrates on which the orientation process is performed is 0 ° ≦ θ1 ≦ A reflection type liquid crystal display device characterized by being at an angle of 30 °.

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