JPH07239471A - Reflection type liquid crystal display device - Google Patents

Abstract

PURPOSE:To obtain a reflection type color liq. crystal display device improving the colorimetric purity and lightness of a displayed color and giving a light display. CONSTITUTION:This liq. crystal display device has a cholesteric liq. crystal layer 30 and a light absorbing layer 40 on the lower substrate 22. The liq. crystal layer 30 has been disposed under an electrode 24 when seen from the user side and the light absorbing layer 40 has been disposed under the liq. crystal layer 30. The liq. crystal layer 30 has mutually different plural wavelength regions of characteristic reflection. The regions Ch(n) are from Anm to Bnm [each of (n) and (m) is an integer of >=1], In both the cases, Anm is >=400nm and Bnm is <=1,000nm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, particularly XY
The present invention relates to a reflection type liquid crystal display device capable of performing large-screen high-definition display and color display at low cost using electrodes.

[0002]

2. Description of the Related Art Liquid crystal display devices have the characteristics of light weight, thin shape and low power consumption, and are widely used as display devices for word processors, personal computers, workstations and the like. Among them, the reflective liquid crystal display device does not require a backlight,
It consumes less power than a transmissive liquid crystal display device, consumes less battery power, and can be used outdoors using external light. Due to these advantages, it is considered that the reflective liquid crystal display device will become the mainstream display device for portable OA equipment in the future.

Most of the software for OA equipment currently sold is compatible with color display, and some of them are difficult to use unless they are displayed in color. Therefore, the reflective liquid crystal display device is also required to be colored. However, if the backlight of the transmissive color liquid crystal display device currently in practical use is replaced with a reflector, the following problems will occur.

(I) Insufficient display brightness (ii) Decrease in color purity of display color The transmission spectrum of the color filter used in the transmission type color liquid crystal display device has a Gaussian function as shown in FIG. It is due to the smooth distribution of the shape. In practice, the wavelength distribution of the visual sensitivity of the human eye must be taken into consideration, but the display brightness corresponds approximately to the area of the transmission spectrum, and the display color approximately corresponds to the width of the wavelength region in which the transmission spectrum is distributed. When the area of the transmission spectrum is increased to increase the brightness of the display, the distribution wavelength region of the transmission spectrum is remarkably increased and the color purity of the display color is remarkably lowered, as indicated by a broken line in FIG. .

(I) and (ii) have a trade-off relationship.
On the other hand, S Mitsui and others have SID92 DIGEST
On page 473, a reflective type color liquid crystal display device in which a light scattering display of a guest host is combined with a color filter is announced. However, the contrast ratio is as low as about 3: 1 and the cost is high because a thin film transistor is used. Also, Martin Schadt is Liqu
id-Cristal Devices and Materials (1991) Vo
l. 1455, pages 214 to 224, a reflective liquid crystal display device using a cholesteric liquid crystal layer exhibiting characteristic reflection in the visible wavelength region is announced. However, there is no mention of the method of colorization and increasing the contrast ratio.

[0006]

As described above, a reflective color liquid crystal display device having a bright display and a high contrast has not been put into practical use. It is an object of the present invention to provide a reflective color liquid crystal display device having a bright display, high contrast, and a simple structure.

[0007]

The summary of the present invention for solving the above problems is as follows.

(1) The upper and lower substrates and the liquid crystal layer, which are arranged to face each other, and an electrode (or an XY electrode) having a drive unit for applying a voltage of two or more values to the liquid crystal layer are provided on the substrate surface, and A liquid crystal display device in which a liquid crystal layer is sandwiched by the substrates, wherein the lower substrate comprises a cholesteric liquid crystal layer and a light absorbing layer, the cholesteric liquid crystal layer is below the electrodes when viewed from a user side, The light absorption layer is disposed below the cholesteric liquid crystal layer, and the cholesteric liquid crystal layer has a plurality of regions having different characteristic reflection wavelength regions, and the characteristic reflection wavelength region is from A _nm to B _nm (n, m). Let Ch (n) be a region where is an integer of 1, 2, 3 ...
_Each A _nm is 400 nm or more, and each B _nm is 1000 nm or less.

(2) The cholesteric liquid crystal layer has regions Ch (1), Ch (2), Ch (3), and the wavelength regions of characteristic reflection for light incident perpendicularly to the layer plane of each region are A, respectively. ₁₁ ≧ 400 nm, B ₁₁ ≦ 550 nm, A ₂₁ ≧ 450
nm, B ₂₁ ≦ 650 nm, A ₃₁ ≧ 550 nm, B ₃₁ ≦ 1
000 nm.

(3) The cholesteric liquid crystal layer has regions Ch (1), Ch (2), Ch (3), and the wavelength region of characteristic reflection for light incident perpendicularly to the layer plane of each region is A. ₁₁ ≧ 400 nm, B ₁₁ ≦ 600 nm, A ₂₁ ≧ 500
nm, B ₂₁ ≦ 1000 nm, A ₃₁ ≧ 400 nm, B ₃₁ ≦
540 nm, A ₃₂ ≧ 560 nm, and B ₃₂ ≦ 1000 nm.

(4) Each area of the cholesteric liquid crystal layer is provided corresponding to a display pixel.

(5) The birefringence of the cholesteric liquid crystal layer is 0.2 or more.

(6) A phase plate and a polarizing plate are laminated on the outer side of the upper substrate in order from the substrate side.

(7) If two phase plates are provided, and the phase plate 2 and the phase plate 1 are arranged in this order from the upper substrate side, the slow axis of the phase plate 2 is made parallel to the alignment treatment direction of the upper substrate, and the phase plate 1 The slow axis is set to 45 ° with respect to the alignment treatment direction of the upper substrate.
5. The liquid crystal display device according to any one of 5.

(8) In (7), the retardation (thickness × birefringence) of the phase plate 2 is set to 25 to 140 nm.

(9) In (6), the angle formed by the transmission axis of the polarizing plate and the alignment treatment direction of the upper substrate is 10 to 35 °.
And

(10) In the above (9), the phase plate 1
Retardation (thickness x birefringence) of 300 to 1000
nm.

[0018]

A method for solving the problems (i) and (ii) described in the prior art will be considered. The color filter utilizes absorption or scattering of light to selectively transmit light in a specific wavelength region, and as long as this principle is used, (i) and (ii) cannot be avoided.

Therefore, the present invention utilizes the characteristic reflection of the cholesteric liquid crystal layer. The cholesteric liquid crystal layer is a layer in which the director orientation, which represents the average orientation direction of liquid crystal molecules, continuously changes clockwise or counterclockwise. The cholesteric liquid crystal layer has a characteristic that its twist direction and rotation direction are the same among the two intrinsic polarized light (elliptical polarized light), and that it reflects light in the wavelength λ region represented by the formula [1], This is called characteristic reflection.

[0020]

## EQU1 ## Pn ₂ <λ <Pn ₁ [1] n ₁ and n ₂ are the larger ones of n _‖ (refractive index in the direction of the director) and n _⊥ (refractive index in the direction perpendicular to the director), respectively. And P is the twist pitch. Since the wavelength range of the characteristic reflection is sufficiently narrow, the reflected light looks colored.

As is clear from the formula [1], the wavelength range of characteristic reflection can be adjusted by changing the pitch of twist. A color filter for a liquid crystal display device, for example, by forming a cholesteric liquid crystal layer in a stripe shape in which the wavelength range of characteristic reflection is changed to a wavelength range corresponding to R, G, and B of a conventional color filter by changing the twist pitch. Can be made.

The color filter using the cholesteric liquid crystal layer has some advantages as compared with the conventional color filters for liquid crystal display devices.

FIG. 4 shows the transmission spectrum of the cholesteric liquid crystal layer. The transmittance decreases by nearly 50% from the wavelength of 510 nm to 590 nm, and characteristic reflection is exhibited in this wavelength region.

As described above, the reflection spectrum of the cholesteric liquid crystal layer exhibits extremely steep rises and falls as compared with the transmission spectrum of the conventional color filter for liquid crystal shown in FIG. In addition, FIG. 3 also shows the reflection spectrum (solid line) of the cholesteric liquid crystal layer whose spectrum area is almost the same as the transmission spectrum of the color filter.

Thus, even if the area of the spectrum is increased to increase the brightness of the display, the increase of the distribution wavelength region of the spectrum is smaller than that of the conventional color filter, and the color purity of the display color is not so lowered.

Since the cholesteric liquid crystal layer reflects light by characteristic reflection, the color filter using this also serves as a reflector. Further, the cholesteric liquid crystal layer is also an optical isolator that produces polarized light from natural light by characteristic reflection, and the color filter also serves as a polarizing plate. In addition, in order to absorb the transmitted light outside the region of the characteristic reflection wavelength and the intrinsic polarized light whose rotation direction in the region is opposite to the twist direction of the cholesteric liquid crystal layer, a light absorber layer is provided behind the cholesteric liquid crystal layer. Set up.

FIG. 5 is a sectional view of the liquid crystal display device of the present invention.
FIG. 6 shows a cross-sectional view when the backlight of the conventional transmissive color liquid crystal display device is replaced with a reflector. In the liquid crystal display device of the present invention, the color filter, the reflection plate and the polarizing plate are integrated and provided directly below the lower electrode 24, so that the entire configuration can be simplified. Further, since the cholesteric liquid crystal layer 30 is used as a color filter, the shadow of the dark display portion, which has been a problem in the conventional reflective liquid crystal display device, is eliminated.

On the other hand, in the conventional reflection type liquid crystal display device, the reflection plate 50 is placed outside the lower substrate 22, and the thickness of the lower substrate 22 is between the electrode 24 and the reflection plate 50. There was a minute away. Therefore, when light is obliquely incident, a shadow of the dark display portion is produced on the reflection plate 50, and the dark surface image becomes 2
It looks heavy and greatly reduces visibility.

The cholesteric liquid crystal layer can be formed, for example, according to F.
H. Kreuzer et al., Mol. Cryst. Liq. Crist., 19
91, Vol. 199, pp. As disclosed in 345 to 378, a cyclic polysiloxane-based polymer liquid crystal can be used. An example of the molecular structure is shown in Chemical formula 1.

[0030]

[Chemical 1]

(However, x is 0.2 to 0.5, and p is 3
Alternatively, 4, q represents an integer of 4 to 6).

The above liquid crystal polymer has a side chain containing a cholesterin skeleton and a side chain not containing a cholesterin skeleton.
As shown in FIG. 23 of the same document, the pitch of twist can be changed by changing the content ratio of the side chains, and the wavelength range of characteristic reflection can be arbitrarily set from the visible wavelength range to the near infrared range. As a result, a cholesteric liquid crystal exhibiting characteristic reflection in the wavelength regions corresponding to the three colors of R, G and B is obtained.

Further, by using a means such as printing, these are formed in stripes on the substrate surface to form Ch (1), Ch (1)
A color filter is obtained by forming the distributions of (2) and Ch (3).

The axis of twist is, for example, T.I. J. Bunning et al., LIQUID CRYSTALS, 1991, Vol.
10, No. 4, pp. As announced in 445-456, it faces the vertical direction of the direction to which shear stress is applied.
Therefore, shear stress can be applied to the cholesteric liquid crystal layer formed in a stripe shape on the substrate in parallel with the substrate surface, and the axis of twist can be oriented in the direction perpendicular to the substrate surface.

In addition to these, a polymer having an aromatic group and an asymmetric structure in the molecule, such as a polyester polymer or a polyamide polymer, is suitable for the cholesteric liquid crystal.

The light absorber may be a black dye, a pigment, a resin in which these are mixed, or the like. Alternatively, a metal film such as chromium used in the black matrix of the transmissive color liquid crystal display device may be used.

The operation and effect obtained by the above are (1) to (1
It is as follows when described in correspondence with each means of 0).

Function and effect 1: By providing the cholesteric liquid crystal layer and the light absorber layer inside the lower substrate, the above (i) to
The problem of (ii) is solved and the shadow of the dark display part is also eliminated.

Function 2: C in the cholesteric liquid crystal layer
Light incident on the h (1), Ch (2), and Ch (3) perpendicularly to the layer plane is 400 to 550 nm and 450 to 65 nm, respectively.
By using those exhibiting characteristic reflection in the wavelength range of 0 nm and 550 to 1000 nm, the wavelength range of characteristic reflection can be set to the wavelength range corresponding to the R, G, and B display colors. As a result, the color filter can be used in addition to the optical isolator and the reflector.

Operational effect 3: In addition, 400 to 600 nm, 500 to 500 nm, respectively, with respect to light incident on the cholesteric liquid crystal layers Ch (1), Ch (2) and Ch (3) perpendicularly to the layer plane.
1000nm, 400-540nm and 560-1000
The wavelength range of the characteristic reflection can be set to the wavelength range corresponding to the display color of cyan, yellow, and magenta by using the one exhibiting the characteristic reflection in the wavelength range of nm. Can be used as a color filter.

Function 4: The distribution of each region in the cholesteric liquid crystal layer is made to correspond to the display pixels, whereby the control of the display color by the drive circuit becomes easy.

Function 5: By using an optically anisotropic substance having a birefringence of 0.2 or more as the cholesteric liquid crystal layer, the wavelength range of characteristic reflection is widened.

Assuming use under a fluorescent lamp, the emission spectrum of the fluorescent lamp is a set of bright lines, and the distribution wavelength width of each bright line is about 50 nm. In the above formula [1], for example, n ₁ = 1.71, n ₂ = 1.51 (birefringence 0.2), P
= 300 nm, the characteristic reflection wavelength region is 453-5.
The width is 13 nm and the width is 60 nm.

When n ₁ = 1.73, n ₂ = 1.51 (birefringence 0.22), and P = 320 nm, the characteristic reflection wavelength region is 483 to 554 nm, which is a width of 71 nm.

Therefore, if the birefringence of the cholesteric liquid crystal layer is 0.2 or more, it can be used under a fluorescent lamp.

As described above, a reflective color liquid crystal display device having a bright display and high display color purity can be obtained.

Since the light transmitted through the driving liquid crystal layer is generally given a polarization dispersion, it is necessary to add S to increase the contrast ratio.
As with the TN-LCD, a phase plate must be used to compensate the polarization dispersion of the transmitted light. The method of deriving the setting conditions of the phase plate will be described below.

In order to reduce the reflectance of the cholesteric liquid crystal layer at the time of dark display, the polarization state of the light incident on the cholesteric liquid crystal layer 30 at the time of dark display is set to the elliptically polarized light whose twisting direction and rotation direction are different from each other. You can do this. At this time, all the light that has entered the cholesteric liquid crystal layer passes through it and is absorbed by the light absorber layer 40 provided behind it. Further, since the elliptically polarized light of the cholesteric liquid crystal layer is an elliptically polarized light whose ellipticity is close to 1 (close to circularly polarized light), the reflectance at the time of dark display is sufficiently reduced even when circularly polarized light having different twist directions and rotation directions is incident. it can.

Therefore, hereinafter, a method of making the light incident on the cholesteric liquid crystal layer at the time of dark display into circularly polarized light having different twist directions and rotation directions will be considered.

First, standardized Stokes parameters (S ₁ , S ₂ , S ₃ ) are introduced to describe the polarization state.
S ₁ , S ₂ , and S ₃ are given by the following equation [2] using the component E _X of the electric field vector in the X-axis direction, the components E _Y of the electric field vector in the Y-axis direction, and the phase difference δ between E _X and E _Y. ~ Is defined in [4].

[0051]

[Number 2] ^{_{S 1 = (E X 2 -E}} Y 2) / (E X 2 + E Y 2) [2] _{S 2 = 2E X E Y cosδ} / (E X 2 + E Y 2) (3) S ₃ = 2E _X E _Y sin δ / (E _X ² + E _Y ² ) [4] Since the sum of squares of S ₁ , S ₂ and S ₃ is 1, any polarization state can be S ₁ , S ₂ and S 3. It can be represented as a coordinate point on a sphere (called a Poincare sphere) having a radius of 1 and having ₃ as the three axes.

The regularity of conversion of the polarization state of incident light by the driving liquid crystal layer will be described by using this standardized Stokes parameter and Poincare sphere display.

The driving liquid crystal layer of the STN-LCD is a chiral nematic layer, and the director (average of the alignment directions of the liquid crystal molecules) has a twist structure in which its orientation is continuously changed with respect to a certain axis. When the light is incident in parallel to the twist axis direction, the eigen polarized light is two elliptically polarized lights having different rotation directions. The major axis of the ellipse is one parallel to the director and the other perpendicular to the director.

The two eigenpolarizations of the chiral nematic layer are approximately located at the concentric points on the Poincare sphere, and the conversion of the polarization state of the light incident on the chiral nematic layer connects the two eigenpolarizations on the Poincare sphere. It is approximately represented as a rotation around a straight line. Since the director of the chiral nematic layer continuously changes its orientation with respect to the axis of twist, the two eigenpolarizations rotate on the Poincare sphere about the S ₃ axis as the light travels. Therefore, the conversion of the polarization state by the chiral nematic layer is represented as precession on the Poincare sphere.

The rotation angle Θ around the line connecting the two intrinsic polarized lights enters the driving liquid crystal layer by placing a polarizing plate on the light incident side of the driving liquid crystal layer so that the director and the transmission axis form 45 °. Light normalized Stokes parameters (a ₀ , b ₀ , c ₀ :
(Coordinate converted value in consideration of rotation of intrinsic polarization) and standardized Stokes parameters (a ₁ , b ₁ , c ₁ ) of emitted light
Is calculated and substituted into the following equation [5] to obtain.

[0056]

Θ = arccos (a ₀ a ₁ + b ₀ b ₁ + c ₀ c ₁ ) [5] IEICE Transactions C-II Vol. J75-C-I
I, No. 3 pp. Tables 1 to 5 show the results of the determination of Θ and its wavelength dependence for various driving liquid crystal layers by using the method described in 149 to 157.

[0057]

[Table 1]

[0058]

[Table 2]

[0059]

[Table 3]

[0060]

[Table 4]

[0061]

[Table 5]

Further, the normalized Stokes parameters (p, q, r) of the two eigenpolarizations on the surface of the chiral nematic layer on the exit side are obtained from the following equations [6] to [8].

[0063]

Equation 4] p = cosψ _O Icosθ _O I [6] q = cosψ _O Isinθ _O I [7] r = sinψ _O I [8] Here, theta _O I alignment treatment direction of the chiral nematic layer surface on the emission side Is twice the azimuth angle θ _O I ′ of
Further, ψ _O I is (a ₀ , b ₀ , c ₀ ), (a ₁ , b ₁ ,
c ₁ ) and θ _O I

Obtained by [9].

[0064]

Ψ _OI = arctan [[(a ₀ −a ₁ ) cos θ _OI + (b ₀ −b ₁ ) sin θ _OI ] / (c ₁ −c ₀ )] ......

[9] Tables 1 to 5 also show the results of determining (p, q, r) and its wavelength dependence for various driving liquid crystal layers. Also,
As an example, the twist angle of 240 ° in Table 2 and Δnd = 0.9
When (p, q, r) obtained for the driving liquid crystal layer of 3 μm is plotted on the Poincare sphere, it becomes as shown in FIG. In this way, the intrinsic polarization of each wavelength is distributed in a very narrow area on the Poincaré sphere.

The setting condition of the phase plate is derived using the above Θ and (p, q, r). The twisting directions of the driving liquid crystal layer and the cholesteric liquid crystal layer are both assumed to be counterclockwise. In this case, the intrinsic polarization transmitted through the cholesteric liquid crystal layer is clockwise elliptically polarized light, and in order to reduce the transmittance of dark display, the normalized Stokes parameter of the light incident on the cholesteric liquid crystal layer is (0, 0, − It should be 1). The normalized Stokes parameter of the incident light E on the driving liquid crystal layer is set to (s, t, u). S ₁ on the Poincaré sphere
Axis, S ₂ axis, when each of the rotation matrix around the S ₂ axis _{R 1, R 2, R 3} , light E transmitted through the driving liquid crystal layer '
Is expressed by the following equation [10].

[0066]

E ′ = R ₃ (−θ _OI ) × R ₂ (−ψ _OI ) × R ₁ (θ) × R ₂ (ψ _OI ) × R ₃ (θ _OI ) × E (10) R ₁ (Θ), R ₂ (ψ), and R ₃ (θ) are expressed by the formula [11],
It is shown by [12] and [13].

[0067]

[Equation 7]

In the above formula [10], E '= (0, 0,
−1), therefore, (s, t, u) is expressed by the following formula [1
4] to [16].

[0069]

S = (1-cos Θ) rp-qsin Θ [14] t = (1-cos Θ) rq + psin Θ [15] u = r ² + (1-r ² ) cos Θ [16] Regarding various driving liquid crystal layers The results of obtaining (s, t, u) and its wavelength dependence are also shown in Tables 1 to 5.

As an example, twist angle 240 °, Δ
When (s, t, u) obtained for the driving liquid crystal layer of nd = 0.93 μm is plotted on the Poincare sphere, it becomes as shown in FIG. As can be seen from FIG. 10, (s, t, u) of each wavelength is distributed in an arc shape (indicated by a broken line in the figure) on the Poincare sphere. This is because the intrinsic polarized light of each wavelength is distributed in a very narrow area on the Poincare sphere as shown in FIG. 9, and the center of rotation of the transmitted light of each wavelength is almost constant.

Next, the setting conditions of the phase plate that gives such wavelength dispersion will be obtained. The conversion of the polarization state by the phase plate is expressed as a rotation around a pair of concentric points located on the equator of the Poincaré sphere. If this is used, two phase plates are used as described below. It is possible to create chromatic dispersion having a polarization state close to that in FIG.

Of the two phase plates, the one closer to the driving liquid crystal layer is the phase plate 2 and the other is the phase plate 1, and θ ₁ , θ ₂ ,
If θ _P is the slow axis of the phase plate 1, the slow axis of the phase plate 2 and the azimuth angle of the transmission axis of the polarizing plate on the Poincare sphere, set θ ₁ , θ ₂ and θ _P as follows. To do.

[0073]

[ _Mathematical formula-see original _document ] [theta] ₁ = [theta] _OI [17] [theta] ₂ = [theta] _OI + 90 [18] [theta] _P = [theta] _OI ± [ _psi ] _OI [19] [theta] ₁ , [theta] ₂ , and [theta] _P using the formulas [17] to [19] The reason for setting like this will be described with reference to FIGS.

Θ _P = θ _OI ± ψ _OI , θ ₁ = θ _OI, and the light R, G, B of each wavelength transmitted through the polarizing plate and the phase plate 1 has an azimuth angle of θ _OI on the Poincare sphere, and , Distributed on a circle centered on the straight line A passing through the equator of the Poincaré sphere [Fig. 1
0 (a)]. Since the figure is a Poincare sphere viewed from the S ₃ axis direction, R, G, and B are points BE and BE '(the azimuth angle is θ _P = θ
It is distributed on a straight line perpendicular to the straight line A, passing through the straight lines B and B ′ included in the equatorial plane at _OI ± ψ _OI and the intersection of the Poincare sphere and the equator. At this time, the rotation angle around the straight line A is Θ
Δnd ₁ (thickness × birefringence) of the phase plate 1 is set so as to satisfy the following [FIG. 10 (b)]. The figure is the surface of the Poincare sphere viewed from the direction of the straight line A, and the circle is the path along which the linearly polarized light incident on the phase plate 1 from the point BE or BE ′ moves on the Poincare sphere due to the optical anisotropy of the phase plate 1. . In addition, FIG.
(S, t, u) 'and (0, 0, -1)' in (b) move to (s, t, u), (0, 0, -1) after passing through the phase plate 2 respectively. It is a point.

From FIG. 10B, when the incident light enters the phase plate 1 from the point BE, the rotation angle around the straight line A is 630.
If it is ° -Θ, it reaches (s, t, u) '. Further, it may be possible to reach (s, t, u) 'after turning around the straight line A for an additional n rounds. The rotation angle at this time is 360n ° + 630 °-
Θ. When the incident light enters the phase plate 1 from the point BE ′, the rotation angle is similarly 360 n ° + 450 ° −θ. From the above, Δnd at the wavelength λ of the phase plate 1
₁ (λ) may be defined by the following equation [20], where λ is the wavelength of the transmitted light.

[0076]

Δnd ₁ = (360 ° n−Θ + 540 ° ± 90 °) λ / 360 ° [20] However, when the incident light is the point BE in the formula [20], the sign of 90 ° is +, It is-when the incident light is at the point BE '.

Δnd for the driving liquid crystal layers in Tables 1 to 5
Tables 6 to 10 show the results of determining ₁ and its wavelength dependence.
The numbers shown in parentheses in Tables 6 to 10 are wavelengths of 550n.
It is the value of Δnd ₁ normalized by m.

[0078]

[Table 6]

[0079]

[Table 7]

[0080]

[Table 8]

[0081]

[Table 9]

[0082]

[Table 10]

Next, θ ₂ = θ _O I + 90 °, and the phase plate 1
The lights R, G, and B of the respective wavelengths transmitted through are moved to the southern hemisphere of the Poincare sphere (the region where the sign of S ₃ is negative) where the intrinsic polarization is located [FIG. 11 (a)].

At this time, R, G, and B are Poincare spheres viewed from the S ₃ axis direction, which is a direction perpendicular to the straight line C whose azimuth angle is θ _OI + 90 ° (that is, a direction parallel to the straight line A). Move to. For each wavelength (s, t, u), an example of which is shown in FIG.
_Are distributed around the eigen-polarized light whose elevation angle is ψ _OI , so by setting the rotation angle around the straight line C to ψ _OI , the light of each wavelength transmitted through the phase plate 2 is (s, t, It is possible to approach the distribution of u) [Fig. 11 (b)].

The retardation Δnd ₂ of the phase plate 2 may be determined by the following equation [21].

[0086]

Δnd ₂ = ψ _OI λ / 360 ° [21] Since ψ _OI in the formula [21] has wavelength dependence, Δnd ₂ should satisfy the formula [21] in all visible wavelength regions. Cannot be specified. Therefore, Δnd ₂ may be set so as to satisfy the equation at the wavelength of 550 nm where the visibility is maximized.

For the driving liquid crystal layers in Tables 1 to 5, the wavelength 5
Table 11 shows Δnd ₂ obtained by substituting ψ _OI of transmitted light of 50 nm into the formula [21].

[0088]

[Table 11]

From its definition, ψ _OI takes a value of 0 to 90 ° or less, but in the case of a twisted nematic liquid crystal layer used in STN-LCD or TN-LCD, ψ _OI is 2
It is in the range of 0 ° to 70 ° or less. 400 in the visible wavelength range
When the range of Δnd ₂ is calculated from the formula [21] with nm to 700 nm, it becomes 25 to 140 nm.

The transmission axis azimuth of the polarizing plate is also determined by ψ _OI . According to the formula [21], the transmission axis of the polarizing plate may form an angle of 20 to 70 ° with respect to the orientation processing direction of the upper substrate on the Poincare sphere viewed from the S ₃ axis direction. Since the angle in the real space is 1/2 of the angle on the Poincare sphere, the angle formed by the transmission axis of the polarizing plate and the alignment treatment direction of the upper substrate may be 10 to 35 °.

Function 6: By laminating the phase plate and the polarizing plate on the outer side of the upper substrate in order from the substrate side, the transmittance during dark display is reduced and the contrast ratio is increased. Also,
The voltage at which each of the R, G, and B pixels or each of the cyan, yellow, and magenta pixels is in dark display is also constant.

Action 7: Two phase plates are used, the slow axis of the phase plate 2 is parallel to the alignment treatment direction of the upper substrate, and the slow axis of the phase plate 1 is in the alignment treatment direction of the upper substrate. To 45 °
By setting so that the light of each wavelength is transmitted through the cholesteric liquid crystal layer during dark display and absorbed by the light absorber layer, the transmittance during dark display is reduced and the contrast ratio is increased.

Function 8: By setting the retardation of the phase plate 2 to 25 to 140 nm, light of each wavelength is transmitted through the cholesteric liquid crystal layer during dark display and absorbed by the light absorber layer, and the transmittance during dark display is obtained. Is reduced and the contrast ratio is increased.

Function 9: By setting the angle between the transmission axis of the polarizing plate and the alignment treatment direction of the upper substrate to be 10 to 35 °,
Light of each wavelength passes through the cholesteric liquid crystal layer during dark display and is absorbed by the light absorber layer, which reduces the transmittance during dark display and increases the contrast ratio.

Action 10: By setting the retardation of the phase plate 1 to 300 to 1000 nm, light of each wavelength is transmitted through the cholesteric liquid crystal layer during dark display and absorbed by the light absorber layer, and the transmittance during dark display is obtained. Is reduced and the contrast ratio is increased.

Although the twist direction of the cholesteric liquid crystal layer is counterclockwise in the above description, it may be clockwise. In that case, E '= (0, 0, 1),
(s, t, u) is calculated by the following equations [22] to [24].

[0097]

S = (1-cos Θ) rp + qsin Θ [22] t = (1-cos Θ) rq-psin Θ [23] u = r ² + (1-r ² ) cos Θ [24] Further, as the phase plate, Currently, polyvinyl alcohol,
Although polycarbonate or the like is used, polyether sulfone, cellulose, an acrylic polymer film or the like may be used instead.

There are two types of color display, one using three colors of red, blue and green, and the other using three colors of yellow, cyan and magenta. The former is superior to the latter in terms of color purity and sharpness of display colors, and the latter is superior in terms of display brightness. Since display brightness is important in a reflective display device, color display using yellow, cyan, and magenta is also effective. In order to realize this, for example, a color filter corresponding to magenta needs a cholesteric liquid crystal that exhibits characteristic reflection in the red and blue wavelength regions.

At present, no cholesteric liquid crystal having a single layer that exhibits characteristic reflection in two wavelength regions has been found. Therefore, a display color corresponding to magenta can be obtained by using two cholesteric liquid crystal layers that have characteristic reflections in the red and blue wavelength regions, respectively.

Similarly, no single layer has been found to exhibit characteristic reflection in the wavelength region of 100 nm or more. Therefore, when performing color display using the three colors of red, blue, and green, the brightness of the display can be increased by using a plurality of cholesteric liquid crystal layers having different characteristic reflection wavelength regions in an overlapping manner. Note that the number of stacked layers can be reduced by using a cholesteric liquid crystal layer with high birefringence.

The method of setting the phase plate and the polarizing plate is not limited to the case of using the cholesteric liquid crystal layer as the color filter, and the cholesteric liquid crystal layer which shows the characteristic reflection in the visible wavelength region and serves as the reflecting plate and the polarizing plate is used. It is also effective in cases.

Further, the present invention can be applied not only to a liquid crystal display device using XY electrodes but also to a liquid crystal display device using a TFT system or MIM system as a driving means, for example, various OA equipments, electric equipments, and acoustic equipments. It is effective as a display device for display panels and operation panels of devices, telephones, facsimiles, cameras, watches and the like.

[0103]

EXAMPLES The liquid crystal display device of the present invention will be described by way of examples.

Example 1 FIG. 1 shows the structure of the liquid crystal display device of the present invention. The upper and lower substrates 12, 22 are XY electrodes 14,
24 and the alignment films 11 and 21, and the liquid crystal layer 10 is sandwiched therebetween. The lower substrate 22 includes a cholesteric liquid crystal layer 30. The XY electrodes 14 and 24 are connected to the drive circuits 15 and 25, respectively. A light absorber layer 4 is provided below the lower substrate.
There is 0.

The upper and lower substrates 12 and 22 are made of glass, and the XY electrodes 14 and 24 are made of ITO. In addition, the alignment films 11 and 12
Reference numeral 1 is made of a polyimide-based polymer, and is oriented by a rubbing method. Orientation processing condition is a cutting depth of 0.4 m
m, rotation speed 1000 rpm, feed speed 33 m / s,
As a result, the tilt angle was set to 4 ° and the twist angle of the upper and lower substrates was set to 240 °.

The driving liquid crystal layer 10 is a nematic liquid crystal (HR9032 manufactured by Rodick, Δn is 0.125).
And chiral agent (S811 manufactured by Merck, content 0.9
Wt%) and the layer thickness is 6.2 μm.

The cholesteric liquid crystal layer 30 is composed of a cyclic polysiloxane polymer, and its molecular structure is shown in Chemical Formula 1 above. The cyclic polysiloxane polymer is described in Mol. Cryst. Liq.
Cryst., Vol. 199, pp. It was synthesized under the conditions described in 345-378.

The content of the side chain containing the cholesterin skeleton was (a) 47%, (b) 37%, (c) 32%, (d) 2
8%, (e) 26%, (f) 24%, (g) 22%,
(H) 18%, (i) 16%, (j) 14%, and the characteristic reflection wavelength regions are (a) 400 nm to 470 n, respectively.
m, (b) 420 nm to 500 nm, (c) 440 nm
˜530 nm, (d) 460 nm to 550 nm, (e)
490 nm to 580 nm, (f) 510 nm to 600 n
m, (g) 530 nm to 620 nm, (h) 550 nm
˜650 nm, (i) 570 nm to 680 nm, (j)
A cholesteric liquid crystal having a wavelength of 600 nm to 710 nm was used. In the cholesteric liquid crystal layer 30, regions Ch (1) and Ch (2) having different characteristic reflection wavelength regions are distributed and formed in stripes. Ch (1) has (a) and (c)
And (f), and Ch (2) used (i) and (j).

First, the cholesteric liquid crystals of (a) and (i) were heated in a liquid crystal state and applied in stripes on a substrate by a printing method. At this time, the cholesteric liquid crystals are not in contact with each other as shown in FIG. Then, using a roller, shear stress is applied in the substrate plane direction,
As shown in (b), each cholesteric liquid crystal was flattened so that adjacent ones were in contact with each other. Further, as shown in FIG. 2C, (c) and (j) were applied on (a) and (i), respectively, and flattened in the same manner. Note that (f) was applied on top of (c) and flattened. At this time, since a step is formed as shown in FIG. 2D, a flattening layer is applied on the step, and the step shown in FIG.
As in (e), the step was eliminated and the film was formed in a stripe shape.

The twist axis of the cholesteric liquid crystal layer was perpendicular to the substrate surface. Parallel to the stripe direction,
XY electrodes were formed so that one stripe corresponds to one electrode. As described above, the wavelength is 400 nm to 600 n
A color filter corresponding to two colors of cyan and R, which exhibits characteristic reflection at m, 570 nm to 710 nm, was prepared. A reflective color liquid crystal display device could be manufactured using the filter.

Example 2 In the liquid crystal display device of Example 1, regions Ch (1), Ch (2), Ch (3) having different characteristic reflection wavelength regions are distributed in a stripe form in the cholesteric liquid crystal layer. Formed.

Ch (1) is a laminate of (i) and (j), C
h (2) is formed with (f), Ch (3) is formed with the laminated body of (a) and (c), respectively, and the wavelength is 570 nm to 710 nm, 510
A color filter corresponding to three colors of R, G, and B showing characteristic reflection in nm to 600 nm and 400 nm to 530 nm was prepared. A reflective full-color liquid crystal display device could be manufactured using this filter.

[Embodiment 3] In the liquid crystal display device of Embodiment 2, Ch (1) is a laminate of (a), (c) and (f), and C is
h (2) is the laminated body of (f), (j), Ch (3) is (a),
Wavelength 400 nm-60 using the laminated body of (b) and (i)
0 nm, 510 nm to 710 nm, 400 nm to 530
nm, and a color filter made of cyan, yellow, and magenta exhibiting characteristic reflection at 570 nm to 680 nm was prepared. A reflective full-color liquid crystal display device could be manufactured using this filter.

Example 4 In the liquid crystal display device of Example 2,
Phase plate 1 and phase plate 2 were added.

From Table 11, the wavelength of the phase plate 2 is 550 nm.
The retardation in this case was 75 nm. In addition, in Table 6
Where Δ is when the compound number in the formula [20] is − and n is 0.
nd ₁Has a wavelength dependence close to that of polycarbonate.
Therefore, polycarbonate is used for the phase plate 1 and the wavelength 55
The retardation at 0 nm was 275 nm.

The slow axis angle of the phase plate 1 is the upper substrate 12
And the slow axis angle of the phase plate 1 was set to be 45 ° with the alignment treatment direction of the upper substrate 12.
Further, the transmission axis angle of the polarizing plate was set to be about 48 ° with respect to the alignment treatment direction of the upper substrate from Table 11.

When the driving voltage dependency of the reflectance of this liquid crystal display device was measured, the reflectance was minimal at around 2.1 V in any of the R, G, and B display colors, and the reflectance of bright display was R. 14%, G was 10%, and B was 14%. Contrast ratio is 1/240 duty drive, R is 7:
1, G was 8: 1 and B was 5: 1.

By adding the phase plate 1 and the phase plate 2 as described above, the reflectance is minimized at almost the same applied voltage value in any display color, and dark display is possible in addition to color display.

[Embodiment 5] In the liquid crystal display device of Embodiment 3,
Phase plate 1 and phase plate 2 were added. Polycarbonate was used for the phase plate 1, and the retardation at a wavelength of 550 nm was 275 nm. The slow axis angle of the phase plate 1 was set parallel to the alignment treatment direction of the upper substrate, and the slow axis angle of the phase plate 1 was set to be 45 ° with the alignment treatment direction of the upper substrate.
Further, the transmission axis angle of the polarizing plate was set to be about 48 ° with respect to the alignment treatment direction of the upper substrate from Table 11.

When the driving voltage dependence of the reflectance of this liquid crystal display device was measured, the reflectance was minimal at around 2.1 V for all of cyan, yellow and magenta, and the reflectance for bright display was 14% for cyan, Yellow was 10% and magenta was 14%. The contrast ratio was 6: 1 for cyan, 7: 1 for yellow, and 5: 1 for magenta in 1/240 duty driving.

By adding the phase plate 1 and the phase plate 2 as described above, the reflectance is minimized at almost the same applied voltage value in any display color, and dark display is possible in addition to color display.

Example 6 In the liquid crystal display device of Example 4, MJ89122 manufactured by Merck & Co. having a Δn of 0.15 was used as the liquid crystal material. From Table 11, the retardation at a wavelength of 550 nm of the phase plate 2 was set to 68 nm. Further, in Table 7, the wavelength dependence of Δnd ₁ when the compound in the formula [20] is − and n is 0 is close to that of polycarbonate. Therefore, polycarbonate is used for the phase plate 1 and the retardation at a wavelength of 550 nm is set to 3
It was set to 51 nm.

Further, the slow axis angle of the phase plate 1 was set parallel to the alignment treatment direction of the upper substrate, and the slow axis angle of the phase plate 2 was set to be 45 ° with the alignment treatment direction of the upper substrate. The transmission axis angle of the polarizing plate was set to be about 45 ° with the alignment treatment direction of the upper substrate from Table 11.

All display areas of R, G and B are 2.1V
The reflectivity becomes minimal in the vicinity, and the contrast ratio is 1/24
In 0 duty driving, R is 8: 1, G is 9: 1 and B
Was 6: 1.

By adding the phase plate 1 and the phase plate 2 as described above, the reflectance is minimized at almost the same applied voltage value in any display color, and dark display is possible in addition to color display.

[Embodiment 7] In the liquid crystal display device of Embodiment 4, HR0008 manufactured by Roddick Corporation having Δn of 0.17 was used as the liquid crystal material.

From Table 11, the retardation of the phase plate 2 at a wavelength of 550 nm was set to 68 nm. Further, in Table 8, Δ when the compound sign in the formula [20] is + and n is 0
The wavelength dependence of nd ₁ is close to that of polyvinyl alcohol. Therefore, polyvinyl alcohol is used for the phase plate 1,
The retardation at a wavelength of 550 nm was 678 nm. Further, the slow axis angle of the phase plate 1 was set parallel to the alignment treatment direction of the upper substrate, and the slow axis angle of the phase plate 2 was set to be 45 ° with the alignment treatment direction of the upper substrate. In addition, the transmission axis angle of the polarizing plate is about 49 with respect to the alignment treatment direction of the substrate above Table 11.
It was set to make °.

All display areas of R, G and B are 2.2V
The reflectivity becomes minimal in the vicinity, and the contrast ratio is 1/24
In 0 duty driving, R is 8: 1, G is 10: 1,
B was 10: 1.

By adding the phase plate 1 and the phase plate 2 as described above, the reflectance is minimized in any display color at substantially the same applied voltage value, and dark display is possible in addition to color display.

[Embodiment 8] In the liquid crystal display device of Embodiment 4, HR0001 manufactured by Roddick Corporation having Δn of 0.13 was used as the liquid crystal material. The twist angle was 260 ° and the chiral agent was contained in an amount of 1.0% by weight.

From Table 11, the retardation of the phase plate 2 at a wavelength of 550 nm was set to 82 nm. Further, in Table 9, Δ when the compound sign in the formula [20] is + and n is 0
The wavelength dependence of nd ₁ is close to that of polyvinyl alcohol. Therefore, polyvinyl alcohol is used for the phase plate 1,
The retardation at a wavelength of 550 nm was set to 626 nm. Further, the slow axis angle of the phase plate 2 was set parallel to the alignment treatment direction of the upper substrate, and the slow axis angle of the phase plate 1 was set to be 45 ° with the alignment treatment direction of the upper substrate. In addition, the transmission axis angle of the polarizing plate is about 54 with respect to the alignment treatment direction of the substrate above Table 11.
It was set to make °.

All display areas of R, G and B are 2.1V
The reflectivity becomes minimal in the vicinity, and the contrast ratio is 1/24
In 0 duty driving, R is 10: 1 and G is 13:
1, B was 12: 1.

By adding the phase plate 1 and the phase plate 2 as described above, the reflectance is minimized at almost the same applied voltage value in any display color, and dark display is possible in addition to color display. FIG. 7 shows an example of mounting the liquid crystal display device of this embodiment on a portable information terminal.

[Embodiment 9] In the liquid crystal display device of Embodiment 4, HR0001 manufactured by Roddick Corporation having Δn of 0.13 was used as the liquid crystal material. The twist angle was 90 ° and the chiral agent was contained in an amount of 0.4% by weight. In addition, X in Example 1
Instead of the Y electrodes 14 and 24, a thin film transistor (TF
T) is used and the driving circuits 15 and 25 are also TFTs.
It was for driving.

From Table 11, the retardation of the phase plate 2 at a wavelength of 550 nm is set to 47 nm. Table 10
Among them, the wavelength dependence of Δnd ₁ when the compound in the formula [20] is − and n is 1 is close to that of polycarbonate. Therefore, polycarbonate is used for the phase plate 1 and the retardation at a wavelength of 550 nm is set to 668 nm. Further, the slow axis angle of the phase plate 1 was set parallel to the alignment treatment direction of the upper substrate, and the slow axis angle of the phase plate 2 was set to be 45 ° with the alignment treatment direction of the upper substrate. In addition, the transmission axis angle of the polarizing plate is about 31 ° with the alignment treatment direction of the upper substrate from Table 11.
It was set so that

All display areas of R, G and B are 2.1V
In the vicinity, the reflectance becomes minimal, and the contrast ratio R is 2
The ratio was 0: 1, G was 32: 1, and B was 22: 1. As described above, reflective color display is possible even in the TFT system.

[Embodiment 10] In the liquid crystal display device of Embodiment 5, HR0001 manufactured by Roddick Corporation having Δn of 0.13 was used as the liquid crystal material. The twist angle was 90 ° and the chiral agent was contained in an amount of 0.4% by weight. In addition, a substrate provided with TFTs was used instead of the XY electrodes of Example 1, and the driving circuit was also for driving the TFTs.

From Table 11, the retardation of the phase plate 2 at a wavelength of 550 nm was set to 47 nm. Table 10
Among them, the wavelength dependence of Δnd ₁ when the compound in the formula [20] is − and n is 1 is close to that of polycarbonate. Therefore, polycarbonate is used for the phase plate 1 and the retardation at a wavelength of 550 nm is set to 668 nm. Further, the slow axis angle of the phase plate 1 was set parallel to the alignment treatment direction of the upper substrate, and the slow axis angle of the phase plate 2 was set to be 45 ° with the alignment treatment direction of the upper substrate. In addition, the transmission axis angle of the polarizing plate is about 31 ° with the alignment treatment direction of the upper substrate from Table 11.
It was set so that

In all the display areas of yellow, cyan, and magenta, the reflectance was minimal at around 2.1 V, and the contrast ratio was 18: 1 for yellow, 18: 1 for cyan, and 22: 1 for magenta.

Example 11 The phase plate 1 and the phase plate 2 were added to the liquid crystal display device of Example 1.

From Table 11, the wavelength of the phase plate 2 is 550 nm.
The retardation in this case was 75 nm. In addition, in Table 6
Where Δ is when the compound number in the formula [20] is − and n is 0.
nd ₁Has a wavelength dependence close to that of polycarbonate.
Therefore, polycarbonate is used for the phase plate 1 and the wavelength 55
The retardation at 0 nm was 275 nm.

Further, the slow axis angle of the phase plate 1 was set parallel to the alignment treatment direction of the upper substrate, and the slow axis angle of the phase plate 2 was set to be 45 ° with the alignment treatment direction of the upper substrate. Further, the transmission axis angle of the polarizing plate was set to be about 48 ° with respect to the alignment treatment direction of the upper substrate from Table 11.

When the driving voltage dependency of the reflectance of this liquid crystal display device was measured, the reflectance was minimal at around 2.1 V for both cyan and R display colors, and the reflectance for bright display was 25% for cyan. , R was 14%. Contrast ratio is 1/240 duty drive, cyan is 6: 1,
R was 7: 1.

As described above, by adding the phase plate 1 and the phase plate 2, the reflectance is minimized in any display color at almost the same applied voltage value, and dark display is possible. This has made it possible to display, for example, an underline in red between a white background color and black characters.

[Embodiment 12] As shown in FIG. 13, a liquid crystal display device was constructed which was composed of a pattern display portion and a matrix display portion and which displayed the names of major cities in Japan and their positions.
A map of Japan and major cities are displayed in the pattern display area. The positions of the major cities are displayed using circular electrodes and circular R filters corresponding to them, and the shapes of the upper and lower electrodes are displayed. The shapes of the color filters are shown in FIGS. 14A and 14B, respectively, and FIG. The shaded portion in FIG. 15 is the R color filter 151, and the laminated body of the cholesteric liquid crystal layers of (f) and (i) in Example 1 was used. The other part is the white display portion 152, and
The laminated body of the cholesteric liquid crystal layers of (a), (d), and (h) therein was used. Example 11 was the same as Example 11 except for the electrode shape and the color filter shape of the pattern display portion. The selected cities are displayed in red, and the locations of unselected cities are displayed in black.

As described above, the present invention is also effective for a liquid crystal display device provided with an electrode having a shape other than the XY electrodes.

[Comparative Example] In the liquid crystal display device of Example 1, the cholesteric liquid crystal layer 30 was replaced with a conventional color filter using a pigment. The transmission spectrum is shown in Fig. 1.
2 shows. Further, the light absorber layer 40 was replaced with a quarter wave plate, a polarizing plate and a reflecting plate. The reflectance of bright display is 10 for each R
%, G is 8%, and B is as low as 8%.

As described above, the reflection type color liquid crystal display device using the color filter using the conventional pigment and the two polarizing plates has a large decrease in display brightness as compared with the display device of the present invention. I understand.

[0149]

As described above, according to the present invention, it is possible to obtain a reflection type liquid crystal display device having a brighter display than the conventional reflection type liquid crystal display device.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing a configuration of a liquid crystal display device of the present invention.

FIG. 2 is a process drawing of a color filter of the liquid crystal display device of Example 1.

FIG. 3 is a spectrum diagram showing normalized maximum values of respective intensities of a reflection spectrum of a cholesteric liquid crystal layer and a transmission spectrum of a color filter using a conventional dye.

FIG. 4 is a transmission spectrum diagram of a cholesteric liquid crystal layer.

FIG. 5 is a schematic cross-sectional view showing a configuration of a liquid crystal display device of the present invention.

FIG. 6 is a schematic cross-sectional view showing the configuration of a conventional liquid crystal display device.

FIG. 7 is a diagram showing an example of installation in a portable information terminal of the present invention.

FIG. 8 is a diagram showing the intrinsic polarization of the driving liquid crystal layer of the liquid crystal display device of the present invention on the Poincare sphere viewed from the S ₃ axis direction.

FIG. 9 is a diagram showing a desirable polarization dispersion state for incident transmitted light of a liquid crystal display device of the present invention on a Poincare sphere viewed from the S ₃ axis direction.

10A is a Poincare sphere viewed from the S ₃ axis direction, showing a method of setting the azimuth angles of the slow axis of the phase plate 1 and the transmission axis of the polarizing plate, and FIG. It is a Poincare sphere surface seen from the direction of the straight line A in a), and is a figure which shows the setting method of the retardation of the phase plate 1.

FIG. 11A is a Poincare sphere viewed from the S ₃ axis direction, showing a method of setting the slow axis of the phase plate 2;
(B) is a Poincare sphere and is a diagram showing a method of setting the retardation of the phase plate 2.

FIG. 12 is a transmission spectrum diagram of a conventional color filter.

FIG. 13 is a diagram showing an example of a display pattern of the liquid crystal display device of Example 12.

FIG. 14 is a diagram showing the shape of upper and lower electrodes of the liquid crystal display device of Example 12.

FIG. 15 is a distribution diagram of color filters of the liquid crystal display device of Example 12.

[Explanation of symbols]

10 ... Liquid crystal layer, 11, 21 ... Alignment film, 12 ... Upper substrate, 1
4, 24 ... Electrodes, 15, 25 ... Driving unit, 16 ... Upper polarizing plate, 17 ... Phase plate, 22 ... Lower substrate, 26 ... Lower polarizing plate, 3
0 ... Cholesteric liquid crystal layer, 31 ... Conventional color filter, 32 ... Flattening layer, 40 ... Light absorber layer, 50 ... Reflector plate, 71 ... Display section, 72 ... Operation section, 73 ... Antenna, 4
50 ... Transmitted light of wavelength 450 nm, 500 ... Wavelength 500 n
m transmitted light, 550 ... Transmitted light of wavelength 550 nm, 600
... transmitted light through the wavelength 600 nm, 650 ... transmitted light through the wavelength 650 nm, theta _OI ... azimuth representing the coordinates of the intrinsic polarization on the Poincare sphere, elevation representing the coordinates on [psi _OI ... Poincare sphere,
R ... Transmitted light of wavelength 650 nm, G ... Transmitted light of wavelength 550 nm, B ... Transmitted light of wavelength 450 nm, A ... Slow axis azimuth of phase plate 1, C ... Slow axis azimuth of phase plate 2, BE, BE ' …
Polarizer transmission axis azimuth, Θ ... Rotation angle of transmitted light around intrinsic polarization of driving liquid crystal layer, R ... Transmission spectrum of conventional color filter for red display, G ... Transmission spectrum of color filter for conventional green display, B ... Transmission spectrum of a conventional blue color filter, 131 ... Pattern display section, 132 ...
Matrix display part 133 ... Red display showing the position of the selected city, 134 ... Black display showing the position of the unselected city, 151 ... Color filter for R display, 152 ... Color filter for white display, 160 ... Substrate, 161 ... Cholesteric liquid crystal (a), 162 ... Cholesteric liquid crystal (i),
163 ... Cholesteric liquid crystal (c), 164 ... Cholesteric liquid crystal (j), 165 ... Cholesteric liquid crystal (f), 166 ... Planarization layer.

Claims (11)

[Claims] 1. An upper and lower substrate and a liquid crystal layer, which are opposed to each other,
A reflection type liquid crystal display device comprising an electrode having a drive unit for applying a binary voltage or more to the liquid crystal layer, the liquid crystal layer being sandwiched between the upper and lower substrates. Is equipped with a cholesteric liquid crystal layer and a light absorption layer,
The cholesteric liquid crystal layer is disposed below the electrode as viewed from the user side, the light absorbing layer is disposed below the cholesteric liquid crystal layer, and the cholesteric liquid crystal layer has a plurality of regions having different characteristic reflection wavelength regions. has, B _nm wavelength region from a _nm of characteristic reflection (n, m is 1, 2, 3, ... integer) when the region is the Ch (n), both a _nm is 4
A reflective liquid crystal display device, characterized in that it is at least 00 _nm and B _nm is at most 1000 nm. 2. The upper and lower substrates and the liquid crystal layer, which are arranged to face each other,
A reflection type liquid crystal display device, comprising: an XY electrode having a driving unit for applying a binary voltage or more to the liquid crystal layer, provided on the substrate surface, wherein the liquid crystal layer is sandwiched between the upper and lower substrates. The substrate is equipped with a cholesteric liquid crystal layer and a light absorption layer,
The cholesteric liquid crystal layer is disposed below the electrode as viewed from the user side, the light absorbing layer is disposed below the cholesteric liquid crystal layer, and the cholesteric liquid crystal layer has a plurality of regions having different characteristic reflection wavelength regions. has, B _nm wavelength region from a _nm of characteristic reflection (n, m is 1, 2, 3, ... integer) when the region is the Ch (n), both a _nm is 4
A reflective liquid crystal display device, characterized in that it is at least 00 _nm and B _nm is at most 1000 nm. 3. The upper and lower substrates and the liquid crystal layer, which are arranged to face each other,
A reflection type liquid crystal display device, comprising: an XY electrode having a driving unit for applying a binary voltage or more to the liquid crystal layer, provided on the substrate surface, wherein the liquid crystal layer is sandwiched between the upper and lower substrates. The substrate is equipped with a cholesteric liquid crystal layer and a light absorption layer,
The cholesteric liquid crystal layer is disposed below the electrode when viewed from the user side, the light absorbing layer is disposed below the cholesteric liquid crystal layer, and the cholesteric liquid crystal layer is Ch.
It has (1), Ch (2), and Ch (3), and the wavelength range of the characteristic reflection for the light incident perpendicular to the layer plane of each region is
₁₁ ≧ 400 nm, B ₁₁ ≦ 550 nm, A ₂₁ ≧ 450 n
m, B ₂₁ ≦ 650 nm, A ₃₁ ≧ 550 nm, B ₃₁ ≦ 10
A reflective liquid crystal display device having a thickness of 00 nm. 4. An upper and lower substrate and a liquid crystal layer, which are arranged to face each other,
A reflection type liquid crystal display device, comprising: an XY electrode having a driving unit for applying a binary voltage or more to the liquid crystal layer, provided on the substrate surface, wherein the liquid crystal layer is sandwiched between the upper and lower substrates. The substrate is equipped with a cholesteric liquid crystal layer and a light absorption layer,
The cholesteric liquid crystal layer is disposed below the electrode when viewed from the user side, the light absorbing layer is disposed below the cholesteric liquid crystal layer, and the cholesteric liquid crystal layer is Ch.
(1), Ch (2), Ch (3), and the wavelength range of characteristic reflection for light incident perpendicularly to the layer plane of each region is A
₁₁ ≧ 400 nm, B ₁₁ ≦ 600 nm, A ₂₁ ≧ 500 n
m, B ₂₁ ≦ 1000 nm, A ₃₁ ≧ 400 nm, B ₃₁ ≦ 5
A reflective liquid crystal display device characterized by having 40 nm, A ₃₂ ≧ 560 nm, and B ₃₂ ≦ 1000 nm. 5. The reflective liquid crystal display device according to claim 1, wherein each wavelength region of characteristic reflection of the cholesteric liquid crystal layer is provided corresponding to a display pixel. 6. The reflection type liquid crystal display device according to claim 1, wherein the birefringence of the cholesteric liquid crystal layer is 0.2 or more. 7. The reflection type liquid crystal display device according to claim 1, wherein a phase plate and a polarizing plate are laminated on the outer side of the upper substrate in order from the substrate side. 8. When the two phase plates are provided, and the phase plate 2 and the phase plate 1 are arranged in this order from the upper substrate side, the slow axis of the phase plate 2 is parallel to the alignment treatment direction of the upper substrate. 7. The reflection type liquid crystal display device according to claim 1, wherein the slow axis is provided so as to form an angle of 45 ° with the alignment treatment direction of the upper substrate. 9. The reflective liquid crystal display device according to claim 8, wherein the retardation (thickness × birefringence) of the phase plate 2 is 25 to 140 nm. 10. The reflective liquid crystal display device according to claim 7, wherein the angle formed by the transmission axis of the polarizing plate and the alignment treatment direction of the upper substrate is 10 ° to 35 °. 11. The reflective liquid crystal display device according to claim 10, wherein the retardation (thickness × birefringence) of the phase plate 1 is 300 to 1000 nm.