JPH02124526A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To make a good-contrast display in black on a white background by providing specific nematic liquid crystal and a member which has the function of a specific phase plate present between polarizing plates. CONSTITUTION:This display device is a birefringence type liquid crystal display device which has the member 10 with the function of the phase plate between the two polarizing plates 9 and 11. In this case, the product R=DELTAn.d.cos<2>theta of the refractive index anisotropy DELTAn of the nematic liquid crystal 8, layer thickness (d), and pretilt angle theta of liquid crystal molecules is 0.4 - 0.8 and the product R'=DELTAn'.d' of the refractive index anisotropy DELTAn' of the member 10 with the function of the phase plate and layer thickness d'(mum)is 0.22+0.55 to 0.42+0.65m or 0.47+0.55 to 0.67+0.65m (m=0-2). Consequently, the good- contrast black display on the white background is obtained.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a birefringence control type liquid crystal display.

(Prior art) There are TN type, DS type, and GH type for liquid crystal display depending on the operation mode.
Although there are many types such as type, DAP type, and thermal writing type, TN type liquid crystal displays are used in most products, including wristwatches, calculators, and measuring instruments. However, with the demand for increased display capacity and larger display area, problems such as insufficient contrast and narrow visual range have arisen in TN type liquid crystal displays, leading to the development of liquid crystal displays with new operating modes. was urgent.

In recent years, birefringence-controlled liquid crystals such as the SBE (super twisted birefringence effect) type described in Japanese Patent Application Laid-Open No. 107020 (107020) have been developed as liquid crystal displays that meet these demands. Display devices are attracting attention. The structure of these birefringence-controlled liquid crystal displays is that two transparent substrates with a transparent electrode formed on at least one side are placed facing each other, the periphery is sealed to form a cell, and a nematic liquid crystal is placed inside the cell. . The distance between the opposing substrates is about 3 to 12 μm, and cyclohexane-based, ester-based, biphenyl-based, and pyridimine-based liquid crystals are used as the nematic liquid crystal. A chiral agent is added to the nematic liquid crystal, and the molecular axes of the liquid crystal molecules are twisted at an angle of 180° to 360° between the upper and lower substrates. Further, the liquid crystal molecules have a pretilt angle in which the molecular axis is tilted by more than 5° with respect to the plane of the substrate due to the action of an alignment layer on the substrate.

In an SBE type liquid crystal display in which the molecular axis has a twist of 270°, polarizing plates are preferably arranged on the outer front and rear surfaces of the substrate, so that the transmission axis of the front polarizing plate is relative to the molecular orientation direction of the front substrate. The best configuration is when the transmission axis of the rear polarizing plate is approximately 30° counterclockwise or approximately 60° clockwise with respect to the alignment direction of the rear substrate.

Among these, the former configuration is displayed in bright yellow in the unselected state,
A black display is obtained in the selected state (yellow mode), and the latter configuration provides a deep blue display in the non-selected state, and becomes transparent in the selected state (blue mode). Also in other birefringent liquid crystal displays, the background color is not achromatic.

On the other hand, a proposal to make this background color achromatic has already been made by the present inventors (Japanese Patent Application Sho Ll-2879
No. 2). In other words, this is a display that utilizes birefringence, such as an SBE type liquid crystal display, and is related to, for example, the layer thickness d of the nematic liquid crystal, the refractive index anisotropy Δn, and the pretilt angle θ(0) of the liquid crystal molecules. The value of R-Δn-d-cos2θ is 0
．． The background and lighting spectra, which fall between 3 and 0.7, are made nearly flat, and a black-and-white display is performed.

(Problem to be Solved by the Invention) However, simply adjusting R between 0.3 and 0.7 and adjusting the absorption axis (or polarization axis) of the polarizing plate will not improve the contrast, whiteness, and transmittance. It was extremely difficult to qualify it as a desired value. In particular, in a transmissive liquid crystal display device that uses a transmissive liquid crystal display and is illuminated from the back, ensuring the contrast of the display will result in a slight coloration, and attempting to maintain whiteness may result in insufficient contrast or a decrease in transmittance. It became.

[Structure of the Invention] (Means for Solving the Problems) The invention according to claim 1 relates to a birefringent liquid crystal display that includes a member having a function of a phase plate between two polarizing plates. , the refractive index anisotropy Δn of the nematic liquid crystal and R as the product of the layer thickness d and the pretilt angle θ of the liquid crystal molecules = Δn−
The value of d-CO82θ falls between 0.4 and 0.8, and R-=Δn as the product of the refractive index anisotropy Δn′ and the layer thickness d゛ (μm) of the member having the function of a phase plate. -ad' value is 0.22+0.55m~0.42+0.65m or 0.47+0.55m~0. I37+0.85m
(m - 0, l, 2).

Further, in the invention as set forth in claim 2, in addition to the above-mentioned member having the function of a phase plate, a 1/4 wavelength plate is added between the polarizing plates.

Note that the value of the pretilt angle θ is the average value of the pretilt angles of individual liquid crystal molecules in the entire liquid crystal layer.

(Function) The value of R mentioned above is closely related to the displayed color, and according to experiments, for example, if it exceeds 0.8, it will have high spectral reflectance and spectral transmittance at a certain specific wavelength, and if it exceeds 0.8, it will have high spectral reflectance and spectral transmittance. , 4, the difference in spectral reflectance and spectral transmittance when a voltage is applied and when no voltage is applied becomes small, resulting in a decrease in contrast.

Therefore, by setting the value of R between 0.4 and 0.8, the background color of the transmitted light or reflected light due to the interference phenomenon is made substantially uniform in the visible light region, making it achromatic, and the selection voltage It has been confirmed through experiments that a combination of a front polarizing plate and a rear polarizing plate can produce a black display on a white background when the voltage is applied. Further, R' of the member having the function of a phase plate is set to 0.
22+0.55m~0.42+0.65m or 0.
47+0.55m~0.67+0.65m (m=0.
It was confirmed that when applying between 1 and 2), the degree of blackness was improved and the black level was lowered when a voltage was applied, and the white level when a voltage was applied was also improved.

Furthermore, by inserting a 1/4 wavelength plate or a 1/2 wavelength plate between the polarizing plates, coloring in areas other than the front can be improved.
It was confirmed that the viewing angle range had expanded.

(Example) The details of this invention will be explained below with reference to the drawings.

FIG. 1 is a sectional view showing an example of a liquid crystal display device using a first embodiment of the invention.

In the figure, conductive electrodes 3 and 4 made of, for example, ITO (Indium Tin Oxide) are formed on first main surfaces 1a and 2a of first and second substrates 1 and 2, which are glass substrates, respectively. The first and second substrates 1 and 2 are maintained at an interval of approximately 7.0 μm such that their first principal surfaces 1a and 2a face each other. Also the first and second
On the first main surfaces 1a and 2a of the substrates 1 and 2, conductive electrodes 3,
Alignment layers 5 and 6 made of polyimide, for example, are formed so as to cover the respective alignment layers 4, and the periphery thereof is sealed with a sealing agent 7 made of, for example, an ultraviolet curing adhesive. A nematic liquid crystal 8 to which a chiral agent is added is sandwiched between the first and second substrates 1 and 2, and the molecular axis of the nematic liquid crystal 8 is set between the first and second substrates 1 and 2 due to the action of the chiral agent.
Range of 180° to 360° between 2, e.g. 200° counterclockwise
It has a torsion of .degree. and has a pretilt angle .theta. of approximately 10.degree., which is greater than 1.degree., with respect to the plane of the first and second substrates 1.2 due to the action of the alignment layer 5.6. Further, the refractive index anisotropy Δn of the nematic liquid crystal 8 is about 0.094, and R=Δn-d-CO62θ as the product of the refractive index anisotropy Δn of the nematic liquid crystal 8, the layer thickness d, and the pretilt angle θ. The value is approximately 0.64 between 0.4 and 0.8. and,
A neutral polarizing plate 9 is arranged on the second main surface lb side of the first substrate 1, and a member 10 having a phase plate function is arranged on the second main surface 2b side of the second substrate 2, for example, a resin having birefringence. A phase plate made of a plate or the like and a neutral polarizing plate 11 are attached. In this way, a desired liquid crystal display 12 is obtained. Here, the arrangement angle of the polarizing plates 9 and 11 is
The polarization axes of the first substrate 1 are set at approximately 80° clockwise and approximately 45° clockwise with respect to the orientation direction of the first substrate 1, and the arrangement of the polarizing plates is set near the blue mode. This corresponds to the case of Further, R--Δn as the product of the refractive index anisotropy Δn and the layer thickness d- (μm) of the member 10 having the function of a phase plate existing between the polarizing plates 9 and 11 is expressed as follows:
0.22+0.55m ~0.42+0.65m m=
It is 0.32 μm as the intermediate value in the range of 0.22 to 0.42 when it is 0, and the stretching axis and the orientation direction of the first substrate 1 are about 110° clockwise with respect to the orientation direction. Further, behind the member 10 having the function of a phase plate and the polarizing plate 11 (in the lower part of the figure), there is a flat light source as an illumination unit 13, which is a combination of a light bulb or a fluorescent light, etc. and a light guide, or an EL (EL).
An electroluminescent (electroluminescent) lamp is provided to provide uniform illumination over the entire surface of the liquid crystal display 12. Furthermore, a liquid crystal display 12 is provided on the side surface (left and right in the drawing) of the second substrate 2.
As the drive circuit section 14, a circuit board 16 on which an electronic component 15 is mounted is electrically connected to the conductive electrode 4 on the protrusion of the second board 2 by a connecting means 17, for example, a flexible sheet or a heat seal. In this way, a liquid crystal display device including the liquid crystal display 12 is formed as a whole.

FIG. 2 is a diagram showing the relationship between wavelength and spectral transmittance in this example, where A represents the state when no voltage is applied, and B represents the state when voltage is applied. As can be seen from FIG. 2, in this embodiment, the spectral transmittance of the background color of the transmitted light due to the interference phenomenon becomes completely flat and achromatic, and when the selection voltage is applied, the polarizing plates 9 and 11 The spectral transmittance is corrected by the member 10 having the function of a phase plate, and a black display with completely flat spectral transmittance can be realized. Here, the color coordinates (x, y) of the background color and lighting color are (0, y), respectively.
321, 0, 343) and (0, 330, 0, 347>), resulting in a completely black display with a white background.

As a result, it is possible to eliminate variations in visibility evaluation due to differences in the visual sense of the observer, and since the background color and display color are achromatic, it is possible to eliminate variations in visibility evaluation due to differences in the visual sense of the observer. Color unevenness is less likely to occur, and color changes from the viewing direction and color changes due to temperature are suppressed. Furthermore, by placing a color filter before or after the polarizing plate 9.11 or on the first substrate 1a, 2a side of the first and second substrates 1.2, color display with good color reproducibility and contrast can be achieved. It is possible.

Further, FIG. 3 shows the spectral transmittance when the applied voltage is changed from around the threshold voltage to the saturation voltage.

In FIG. 3, B represents when a selection voltage is applied, E represents when a non-selection voltage is applied, and C and D represent when a voltage between them is applied. As can be seen from Figure 3, in this example, the spectral shape of the spectral transmittance does not change due to the applied voltage, only the average transmittance changes, and there is no color change when performing intermediate display, and the self-level This shows that the black level changes from Therefore, compared to conventional birefringent liquid crystal displays, halftone display can be performed better. In addition, especially when performing color display in combination with color filters, etc., there is no color change in halftone display (during full color display) as with conventional LCD displays, making it possible to display full color with excellent color reproducibility. It is.

Note that for a liquid crystal display having a structure similar to that of this embodiment, the value of R and the display quality have a relationship as shown in the following table.

The following margin table Table 1 has the same configuration as the embodiment shown in FIG. It is a table showing changes in whiteness, brightness, and contrast ratio. As can be seen from the same table, if R is reduced to about 0.4, the whiteness of the background color is good, but the contrast ratio decreases and the brightness also becomes dark, making it necessary to illuminate from behind the liquid crystal display. It's coming. On the other hand, increasing R from 0.6 to 0,
When it is set to 75, a liquid crystal display with good whiteness, background color brightness, and contrast ratio is obtained. Furthermore, when R exceeds 0.8, although the background brightness and contrast ratio are good,
The background becomes slightly colored. Further, the value of R- of the member 10 having the function of a phase plate is achromatic at R'-0.32, but it deviates from this value and ranges from 0.22+0.55m to 0.42
Lower limit of range 0.2 when +0.65m is m-0
2 or the upper limit value R--0, 42, the coloring increases and becomes colored. Furthermore, 0.22+0.55m~0
．． 4200, (median value of the range R-=0.92 when m=1,2 for i5m, or R--■, 52 is also achromatic, but when viewed from other than the front, the background color etc. The color change increases as the value of m increases, so it is not practical when the value of m is 3 or more.
．． 55m to 0.42 + 0.65m, where m = 1.2, it is most desirable that the value of R' is in the middle or close to the upper and lower limits of each range. As the color increases, the color becomes larger and the color becomes m.
This is the same as when =o. Therefore, the value of R' of the member 10 having the function of a phase plate is preferably around R-=0.32.

Note that the twist angle of the liquid crystal molecules can range from 180° to 360°, but it is preferably 210° or more depending on the brightness of the background color, and when operated at 270° or more, it has hysteresis characteristics.

Therefore, the twist angle of liquid crystal molecules is 210° to 270°.
A range of about 270° is desirable, and from the viewpoint of good contrast ratio, brightness, and whiteness, a range of about 270° is most desirable.

Next, a second embodiment of the invention set forth in claim 1 will be described. This embodiment is similar in structure to the embodiment shown in FIG. 1, but the arrangement angle of the polarizing plates 9 and 11 is
．． The polarization axes of 11 are set to be approximately 135 degrees clockwise and approximately 45 degrees clockwise with respect to the orientation direction of the first substrate 1, and the arrangement of the polarizing plates, etc. is near the yellow mode. This corresponds to the case of Further, the value of R' of the member 10 having the function of a phase plate is 0.47+0.55m to 0. [
Range 0.47~ when m=o at i7 0.85m
It is 0257 μm as an intermediate value of 0.67, and the orientation direction of the stretching axis and the first substrate 1 is about 110° clockwise with respect to the orientation direction. Further, the twist angle of the liquid crystal molecules between the first and second substrates 1.2 is 270° counterclockwise, the pretilt angle θ is 10°, the refractive index anisotropy Δn of the nematic liquid crystal 8 is 0.094, and R=0. .64, which is similar to the embodiment shown in FIG. The relationship between wavelength and spectral transmittance in this example is the same as that shown in Figure 2, and the spectral transmittance of the background color of the transmitted light due to the interference phenomenon is completely flat, only the transmittance is different. , it is possible to achieve a black display on an achromatic bright background. Part 10 R- which has the function of a phase plate
The value of R-=0.57 results in an achromatic color, but it deviates from this value and ranges from 0.47 + 0.55m to 0. [i700,
Lower limit of the range R-=0.4 when m=0 at 65m
7 or approaches the upper limit value R-=0.67, the coloring increases and becomes colored.

Furthermore, 0.47+0.55m~0.67〇, [f5m
When m = 1, 2, the intermediate value of the range R- = 1.17
, or R-=1.77 will result in an achromatic color, but as the value of m increases, the color change in the background color etc. will increase when viewed from other than the front, so it is not practical when the value of m is 3 or more. Not on point. Also, 0.47+0.55m~0.67+0
Among the individual ranges when m = 1, 2 at 85 m, it is most desirable for the value of R' to be an intermediate value, and as it approaches the upper and lower limits of each range, the coloring increases. It is the same as in the case of m -0 that the color becomes different.

Therefore, the value of R- of the member 10 having the function of a phase plate is:
It is preferable that R-=0.5'l.

Furthermore, as in the previous embodiment, the twist angle of the liquid crystal molecules is preferably in the range from 210° to 270°.
Further, the angle is preferably around 270°.

FIG. 4 is a diagram showing a third embodiment of the invention as claimed in claim 1, and parts corresponding to those in FIG. 1 are given the same reference numerals. This embodiment differs from the embodiments described so far in the arrangement of the member 10 having the function of a phase plate, and the member 10 having the function of a phase plate is installed between the polarizing plate 9 and the first substrate 1. are doing.

This embodiment not only has the same effect as the previous embodiment, but also provides a member 10 having the function of a phase plate between the polarizing plate 9 on the side where external light is incident and the first substrate 1. As a result, compared to the case where the polarizing plate 11 is installed between the polarizing plate 11 and the second substrate 2, unevenness in the background color of the liquid crystal display 12 due to unevenness in plate thickness, unevenness in stretching, etc. of the member 10 having the function of a phase plate is reduced. is greatly reduced, making it possible to realize a liquid crystal display with no practical problems. The effect of arranging the member 10 having the function of a phase plate between the first substrate 1 and the polarizing plate 9 is particularly noticeable in a reflective type, but the effect is also recognized in a transmissive type. This is because external light, which is ambient light, enters the liquid crystal display and it partially functions as a reflective type.

Next, a case will be described in which there are a plurality of members 10 having the function of phase plates. FIG. 5 is a diagram showing a fourth embodiment of the invention as claimed in claim 1, and parts corresponding to those in FIG. 1 are given the same reference numerals. This embodiment differs from the embodiments described so far in the configuration of the member 10 having the function of a phase plate. That is, the member 10 having the function of a phase plate is
It is arranged between the substrate 2 and the polarizing plate 11, and consists of a phase plate 10a and a 172-wavelength plate 10b stacked one on top of the other in order from the side closer to the second substrate 2. Here, the values of R- of the phase plate 10a and the 172 wavelength plate 10b are both about 0.32 μm, and 0.32 μm.
22+ 0.55m ~0.42〇, m=0 at 65m
This is the intermediate value when Further, the extension axis of the phase plate 10a is approximately 110' clockwise with respect to the orientation direction of the first substrate 1.
Further, the angle between the fast axis (or slow axis) of the half-wave plate LOb and the absorption axis (or polarization axis) of the adjacent polarizing plate 11 is set to be about 45°. It is.

FIG. 6 shows a configuration similar to this embodiment, with a 172-wave plate 10
It is a figure which shows the viewing angle range (inside a polygonal line) in the case where there is no b (A in the figure) and the case where it is present (B in the figure). In the figure, the directions of the X-axis and Y-axis are approximately parallel to the rubbing direction of the first substrate 1 on the front side and the second substrate 2 on the rear side for the observer, and The angle value indicates the angle of inclination of the display surface from the vertical direction.

As can be seen from FIG. 5, by adding the 1/2 wavelength plate 10b, the viewing angle range is expanded in the entire viewing direction. Although not shown here, the spectral transmittance curve at the front is the same as that shown in FIG. 2 regardless of the presence or absence of the 1/2 wavelength plate 10b.

The following Table 2 shows the fast axis (or slow axis) of the 1/2 wavelength plate 10b and the absorption axis (or polarization axis) of the adjacent polarizing plate 11.
3 is a table showing the relationship between the angle φ formed with the whiteness of the background color and the whiteness of the background color.

As shown in Table 2 below, when the angle φ is set at 45°, when viewed from the front, the background color becomes transparent white, but the display becomes black, and the viewing angle range also expands. ing. When the angle φ is in the range of approximately 40 to 50 degrees, the background color becomes slightly colored, but basically black and white display is possible, and as the angle φ exceeds this range, the coloring becomes noticeable. The colored color is the value of R or R'
Depending on the value of Furthermore, which of the fast axis and the slow axis of the half-wave plate 10b is selected as the reference for the angle φ depends on the alignment direction of the liquid crystal molecules,
It depends on the direction of the stretching axis of the part 10 having the function of a phase plate, the twist angle of the liquid crystal molecules, etc. From Table 2, it is most desirable that the angle φ is about 456, and this range is approximately 40° to 50°.

FIG. 7 is a diagram showing an embodiment of the invention as claimed in claim 2, and parts corresponding to those in FIG. 1 are given the same reference numerals.

This embodiment is similar in structure to the embodiment shown in FIG.
has been established. In addition, the R- value of the wave plate 20 to ■ is approximately 0.
．． 1+iμm, and the angle formed by the fast axis (or slow axis) of the wave plate 20 and the absorption axis (or polarization axis) of the adjacent polarizing plate 11 is the same as in the embodiment shown in FIG. Approximately 4
It is set so that the angle is 5°. The spectral transmittance characteristics of the configuration of this embodiment when viewed from the front are the same as those shown in FIG. 2 both when no voltage is applied and when voltage is applied, regardless of whether or not the wavelength plate 20 is provided. Ta.

FIG. 8 shows a configuration similar to this embodiment, with a 1/4 wavelength plate 20
7 is a diagram showing the viewing angle range in the case where there is no (A in the figure) and the case where there is (B in the figure), and corresponds to FIG. 6. 1/4
By adding the wavelength plate 20 to the configuration, the viewing angle range is expanded in the entire viewing direction. Furthermore, by comparing FIG. 6 with FIG. 3, it can be seen that the viewing angle range is slightly wider when using the 1/4 wavelength plate 20 than when using the 1/2 wavelength plate 10b. . Also, the angle φ is the fifth
As in the embodiment shown in the figure, the angle is most preferably about 45 degrees, and this range is approximately 40 degrees to 50 degrees.

Regarding the position of the member 10 having the function of a phase plate, if it is placed between the polarizing plates 9 and 11, it should be placed between the first substrate 1 and the polarizing plate 9 or between the second substrate 2 and the polarizing plate 12. Regardless of the position between the two, it is possible to flatten the spectral transmission spectrum and obtain a liquid crystal display with good whiteness/blackness. Also, the first
A member 10 in which the substrate 1 or the second substrate functions as a phase plate
Even if both are used, the same effects as in the previous embodiments can be obtained.

Furthermore, up to now, the position of the 1/2 wavelength plate 10b or the 174 wavelength plate 20 has been explained using an example in which the position is in contact with the phase plate constituting the member 10 having the function of a phase plate. It may be arranged so that it is in contact with 2. However, considering the magnitude of color change from the viewing angle range of the background color, the 172-wave plate 10b or the 1/4-wave plate 20 and the above-mentioned phase plate are
It has been confirmed through experiments that the best position is when they are in contact with each other.

Although the above description has been made using a transmissive liquid crystal display as an example, it is clear that a reflective liquid crystal display may also be used.

[Effects of the Invention] The invention according to claim 1 is a liquid crystal display device that utilizes interference color due to birefringence, and the value of R-Δn-d・cos2θ is set to 0.
．． 4 to 0.8, as the product of the refractive index anisotropy △n' and the layer thickness (μm) of the part having the function of a phase plate located between each polarizing plate attached to two substrates. R'-Δn-
・d- is 0.22+ 0.55m ~ 0.42+ 0.8
5m or 0.47+ 0.55m~0.87〇, 8
5m (m=0.l, 2). Further, the invention according to claim 2 has a configuration in which a quarter wavelength plate is further added between the polarizing plates in addition to the invention according to claim 1. As a result, in the present invention, the background color of the reflected or transmitted light due to the interference phenomenon has a completely flat spectral shape and is white, and the displayed color is black, resulting in a display with good whiteness and contrast. especially,
In the invention set forth in claim 2, the viewing angle range is also widened.

In this way, an ideal black-and-white display can be realized for a liquid crystal display, eliminating differences in visibility due to visual perception. In addition, color unevenness within the plane of the liquid crystal display is reduced, yield is improved, and color changes with respect to viewing angle direction and temperature are small, and color display can be performed. In particular, a transmissive liquid crystal display can realize a black-and-white display with sufficient contrast, and even when displaying in color, it can produce good gradation, so it can realize a full-color display with good color reproducibility. Furthermore, compared to conventional liquid crystal displays, only a member having the function of a phase plate is added, so it is very advantageous in terms of cost, and it is possible to provide an inexpensive and high-quality liquid crystal display.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of a liquid crystal display device using a first embodiment of the invention as claimed in claim 1, FIG. 2 is a diagram showing an example of the relationship between wavelength and spectral transmittance in this invention, FIG. 3 is a diagram showing the spectral transmittance when the applied voltage is changed in this invention, and FIG. 4 is a cross-sectional view showing an example of a liquid crystal display device using the third embodiment of the invention as set forth in claim 1. , FIG. 5 is a sectional view showing an example of a liquid crystal display device using the fourth embodiment of the invention as claimed in claim 1, and FIG. 6 is a diagram showing an example of the viewing angle range of the embodiment shown in FIG. , FIG. 7 is a sectional view showing an example of a liquid crystal display device using an embodiment of the invention as claimed in claim 2, and FIG. 8 is a diagram showing an example of the viewing angle range of the embodiment shown in FIG. 7. . 1... First substrate 2... Second substrate 3.4.
...Conductive electrode 8...Nematic liquid crystal 9.11
... Polarizing plate 10 ... Member having the function of a phase plate 20 ...
...1/4 wavelength plate agent Patent attorney Nori Chika Ken Yudo Sakuo Kikuo/? , Pekyo director's side hi committee mouth i ← yo

Claims (2)

[Claims] (1) First and second electrodes with conductive electrodes formed on the first main surface side
a substrate, the molecular axis being 1 with respect to the plane of the first and second substrates;
has a pretilt angle θ greater than
and a nematic liquid crystal sandwiched between the second substrates with a twist in the range of 180° to 360°, a polarizing plate attached to the second main surface side of the first and second substrates, and a polarizing plate between the polarizing plates. a member having the function of a phase plate existing in the nematic liquid crystal, and the refractive index anisotropy Δn and the layer thickness d
(μm) and the value of R=Δn・d・cos^2θ as the product of the pretilt angle θ (°) is between 0.4 and 0.8, and the refraction of the member having the function of the phase plate is The value of R'=Δn'・d' as the product of rate anisotropy Δn' and layer thickness d' (μm) is 0.22+0.55m to 0.42+0.65m or 0.47+0.55m to 0.67+0 .65m (m=0
, 1, 2). (2) The liquid crystal display according to claim 1, characterized in that a quarter wavelength plate is added between the polarizing plates.