JP3267861B2 - Reflection type liquid crystal display element and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflection type liquid crystal display device having no external light source such as a backlight on the back of a liquid crystal cell, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, the GH (guest host) system has been used for a reflection type liquid crystal display device because it is a display mode in which brightness has priority over contrast among display modes. A reflection type liquid crystal display device shown in FIG. 17 is a first improved type in which a low contrast is improved.

The liquid crystal display device is disclosed in the proceedings of the 21st Liquid Crystal Symposium on Liquid Crystals (pp. 320-321). A GH liquid crystal is provided between a transparent upper substrate 112a and a lower substrate 112b which are arranged opposite to each other. The transparent electrode 113, the light diffusion layer 114, and the alignment film 115a are sequentially formed on the liquid crystal layer side of the upper substrate 112a with the layer 111 interposed therebetween, and the reflective electrode 116 having a specular property is formed on the liquid crystal layer side of the lower substrate 112b. , Λ / 4 layer 118
Are sequentially formed, and the liquid crystal molecules of the GH liquid crystal layer 111 are aligned in parallel. Therefore, in this configuration, the polarized light that has not been absorbed by the GH liquid crystal layer 111 passes through the λ / 4 layer 118 and the flat reflective electrode 116 and is again absorbed by the liquid crystal layer. Improve by a minute.

As a second improved type, a technique of twisting a transmission type liquid crystal layer from .pi. To 2.pi.
No. 8130.

On the other hand, in the ECB (voltage controlled birefringence) mode, a high contrast is obtained because a polarizing plate is used, but the brightness is reduced accordingly. FIG. 18 shows a reflection type liquid crystal display device in which the number of polarizing plates is one and the brightness is improved. The liquid crystal display element is AM-L
CD95 (Digest of TechnicalP
arers, 1995, pp. 27-30), in which a liquid crystal layer 101 is sandwiched between a transparent upper substrate 102a and a lower substrate 102b which are disposed to face each other, and the upper substrate 10
While a transparent electrode 103 is formed on the liquid crystal layer side of 2a,
A mirror reflector 106 serving also as an electrode is formed on the liquid crystal layer side of the lower substrate 102b, and a polarizing plate 104 and a scattering plate 105 are sequentially formed on the outer surface side of the upper substrate 102a.

[0006]

However, although such a reflection type liquid crystal display device and its improved type have been proposed, optimization of brightness and contrast is insufficient, and parallax is generated. In addition, in particular, there is a problem that it is completely impossible to perform color display by mounting a color filter.

That is, the λ / 4 plate used in the first improved type of the GH system has no wavelength characteristic, and depending on the wavelength, the λ / 4 plate
The four conditions were not satisfied, and the contrast was not improved over the entire visible light range. For this reason, there has been a problem that the contrast when displayed is insufficient.

Further, a technique for twisting a liquid crystal layer as a second improved type of the GH system is a technology disclosed for a transmission type. In addition, the effect of this technique is disclosed as an effect of improving steepness near a threshold, not an optical characteristic. Therefore, when designing as a reflection type,
It was impossible to convert the numerical range of the transmission type as it is or by a simple calculation method. It is for the following two reasons.

In JP-A-59-28130,
It discloses that the torsion angle is changed from π to 2π radians, but does not disclose the relationship between the torsion angle and the brightness within this numerical range. The transmissive type can rely on the backlight even if the brightness is slightly inferior, but the reflective type is the first condition to secure the brightness, and it is necessary to study to secure a little more brightness.

The optical characteristics of the reflection type cannot be derived from those of the transmission type by simple calculation (for example, 倍 times the transmission type liquid crystal display element). The liquid crystal layer of the transmission type liquid crystal display element is continuous, whereas the reflection type liquid crystal layer is divided into two, and a reflection surface corresponding to a reflection plate exists between them. For this reason, when the liquid crystal layer is in parallel alignment, it can be replaced by a simple calculation that mathematically multiplies the thickness of the liquid crystal layer by several times.In the case of twisted alignment, the optical rotation dispersion for twist and the phase conversion of elliptically polarized light are taken into consideration. Must-have. JP-A-59-28130 discloses a reflective device configuration, but does not disclose the optical characteristics of the reflective torsional alignment. Is not something that can be analogized.

In the improved type of ECB mode, although the brightness and the viewing angle are improved, the parallax is reduced after passing through a substrate made of glass or the like and then passing through a polarizing plate and a scattering plate. There was a problem that it became larger.

The reflection type liquid crystal display device of the present invention has been made in view of the above-mentioned problems, and a brighter and more contrast image is obtained by focusing on the reflection type liquid crystal display device and optimizing each condition. Another object of the present invention is to provide a reflective display element excellent in the above. Another object of the present invention is to realize a reflector liquid crystal display device having a color filter and capable of multicolor display.

[0013]

According to a first aspect of the present invention, there is provided a reflective liquid crystal display device comprising a pair of transparent substrates, at least one of which is sandwiched between the pair of substrates. A liquid crystal layer containing the obtained polychromatic dye, an electrode for applying a voltage to the liquid crystal layer, and the pair of substrates.
A scattering layer disposed between the transparent substrate and the liquid crystal layer, and a reflective layer having a flat reflective surface disposed between the liquid crystal layer and the substrate that may not be transparent among the pair of substrates. , The anti
A quarter-wave layer disposed between the light-emitting layer and the liquid crystal layer, and the optical retardation of the quarter-wave layer is determined for each pixel according to the wavelength of the color corresponding to the pixel. And the liquid crystal layer is further added with a chiral agent
Liquid crystal molecules are spiraled perpendicular to the surface of a pair of substrates
It is twisted about the axis, and from one of the pair of substrates to the other
Liquid crystal molecules with a twist angle of 140 degrees or more and 250 degrees or less
It is characterized by being in the range .

The condition of the quarter wavelength of the quarter wavelength layer naturally depends on the wavelength of the color. Therefore, by changing the retardation for each pixel according to the color corresponding to that pixel, a more sufficient contrast can be obtained when performing color display, and the color reproducibility can be improved.

[0015]

[0016]

In the GH system having a structure in which the alignment of liquid crystal molecules is twisted between upper and lower substrates, light passes through the liquid crystal layer while rotating its polarization plane. At that time, light is absorbed by the polychromatic molecules. Thereby, sufficient light absorption can be obtained without using a polarizing plate when no voltage is applied (in the case of a GH liquid crystal having a positive dielectric anisotropy).

Therefore, the present inventors have studied in detail the twist angle and brightness of liquid crystal molecules in order to realize a brighter display more suitable for the reflection type. as a result,
The range of the twist angle disclosed in JP-A-59-28130 is not always the best with respect to the brightness in the voltage application state (ON state), and the brightness in the ON state greatly depends on the twist angle. I understand. Further, the inventors have found that there is an optimum twist angle which is the brightest among the twist angles examined by the inventors and does not cause hysteresis.

FIG. 7 shows the torsion angle dependence of the light reflectance when a voltage is applied to the liquid crystal. The applied voltage was constant at all twist angles. As shown in FIG. 7, it can be seen that the reflectance at the time of applying a voltage changes by changing the twist angle. Of these, there are regions where the reflectivity is highest around the torsion angles of about 0 degree and about 180 degrees, and 140 to 2 degrees.
It has been found that the brightest display can be obtained by producing a GH liquid crystal with a twist angle in the region of 50 degrees.

As a result of such examination, in the above configuration,
The liquid crystal molecules of the GH liquid crystal layer are twist-aligned in a range of a twist angle from 140 to 250 degrees from one of the pair of substrates to the other. In this range, the rotation of the polarization plane of the light cannot follow the change in the orientation of the liquid crystal molecules, so that sufficient light absorption occurs. Since this light absorption has no difference in wavelength characteristics, light absorption is performed over the entire visible light. Thereby, in the twisted GH method, more suitable for the reflection type,
It is bright and has good contrast.

In addition, since the reflective layer having a flat reflective surface is used as the internal reflective layer having no parallax, the liquid crystal molecules can be easily oriented at the set twist angle, and the set twist can be achieved. Display unevenness does not occur due to a slight deviation of the corner or the cell thickness. In addition, even if a reflective layer having a flat reflective surface is used to facilitate orientation, the diffused layer is arranged with the reflective layer sandwiching the liquid crystal layer. Therefore, there is no fear that the viewing angle is narrowed.

Furthermore, the optical retardation is
Change according to the wavelength of the color corresponding to that pixel
The上 wavelength layer is provided on the reflective layer, so that in a dark display without applying a voltage (in the case of a GH liquid crystal having a positive dielectric anisotropy), a polychromatic dye is applied when passing through the liquid crystal layer. Light that has not been absorbed is also efficient when passing through the liquid crystal layer again after reflection .
Ku will be absorbed. That is, light that is not absorbed by the polychromatic dye when passing through the liquid crystal layer is polarized into circularly polarized light by passing through the quarter-wavelength layer, and is reflected while the polarization is preserved by the reflective layer. . Then, when the light again passes through the quarter wavelength layer, it becomes linearly polarized light rotated by 90 degrees and is absorbed by the polychromatic dye. Therefore, the dark display becomes better, the reflected light intensity is much smaller than the incident light intensity, and the contrast can be further improved. Moreover,
Since it is a reflective layer having a flat reflective surface, polarized light can be preserved, and an ideal operation can be expected in a configuration in which such polarized light needs to be preserved.

According to a second aspect of the present invention, there is provided a reflective liquid crystal display device, wherein at least one of the substrates is a pair of transparent substrates.
A liquid crystal layer optically birefringent sandwiched between substrates of
An electrode for applying a voltage to the liquid crystal layer, and the pair of substrates
Layer disposed between the transparent substrate and the liquid crystal layer
And a polarizer disposed between the scattering layer and the liquid crystal layer,
A substrate which is not required to be transparent among a pair of substrates and a liquid crystal layer;
A reflective layer having a flat reflective surface disposed between
Between the layer and the liquid crystal layer or between the liquid crystal layer and the polarizer
A retardation layer disposed on the substrate, wherein the optical characteristics of the retardation layer
Pixelated retardation for each pixel
It is characterized by being changed according to the wavelength of the color .

Same as １ ／ wavelength condition of の wavelength layer
Of the apparent retardation between the retarder and the liquid crystal layer
The compensation conditions naturally differ depending on the wavelength of the color. But
Therefore, for each pixel, the retardation depends on the color corresponding to that pixel.
By changing the options, when color display is performed,
Sufficient contrast is obtained and color reproducibility is improved
You.

In a liquid crystal cell in which an ECB mode, a retardation layer, and a single polarizer are combined, the voltage applied to the liquid crystal layer is controlled to reduce the apparent retardation between the retardation layer and the liquid crystal layer by ４. By setting the wavelength condition and 0, and switching between these values, a bright display and a dark display are performed. If the polarization is not preserved, the retardation of the light passing through the liquid crystal layer is largely deviated from the set value. However, according to this, since the reflective layer has a flat reflective surface, the polarized light is preserved in the reflective layer, and the retardation of the light passing through the liquid crystal layer does not largely deviate from the set value. That is, in the relationship between the retardation and the reflectance, bright display and dark display using the maximum value and the minimum value can be performed, so that the brightness and the contrast can be improved. Incidentally, even if a reflective layer having a flat reflective surface is used, the diffused layer is disposed with the liquid crystal layer interposed between the reflective layer and the reflective layer.
Since a wide viewing range can be ensured, there is no fear that the viewing angle is narrowed.

In this case, a polarizer and a diffusion layer are provided in the liquid crystal cell, and a diffusion layer is arranged on the substrate side of the polarizer.
Since the retardation layer is designed to be disposed closer to the liquid crystal layer than the polarizer, the function of each layer can be effectively obtained, and a high-definition display without parallax can be realized.

According to a third aspect of the present invention, there is provided a method of manufacturing a reflection type liquid crystal display device, wherein at least one of the substrates is a pair of transparent substrates, a liquid crystal layer sandwiched between the pair of substrates, and a voltage is applied to the liquid crystal layer. An electrode for applying a voltage, a reflective layer disposed between the liquid crystal layer and the non-transparent substrate of the pair of substrates, and an optically birefringent such as a quarter-wave layer or a retardation layer. A reflective birefringent layer, wherein the optical retardation of the birefringent layer is changed according to the wavelength of the color for each of red, green and blue pixels. In the production of the birefringent layer, after adjusting the thickness of the material layer to be the birefringent layer so as to have a retardation according to the red wavelength, only the blue pixel portion, the retardation according to the green wavelength With film thickness and retardation according to blue wavelength After that, each pixel portion of green and blue is etched by the difference between the film thickness having retardation corresponding to the red wavelength and the film thickness having retardation corresponding to the green wavelength. Features.

According to this, the birefringent layer, which is changed according to the wavelength of the color for each of the red, green and blue pixels,
Since it can be manufactured in a smaller number of steps than in the case of manufacturing separately for each color, the manufacturing steps of the reflective liquid crystal display element capable of color display according to the first and second aspects can be simplified.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of [Embodiment 1] The present invention will be described with reference to FIGS. 1 to 14 are as follows.

FIG. 1 shows a reflection type liquid crystal display element (hereinafter referred to as a first precondition liquid) which is a premise of the reflection type liquid crystal display element of the present embodiment.
FIG. 1 is a cross-sectional view showing the structure of a liquid crystal display element .

As shown in FIG. 1, the first premise liquid crystal display element comprises a GH (guest host) liquid crystal cell 61 and modulation control means 50 connected to the GH liquid crystal cell 61.

The GH liquid crystal cell 61 has a pair of transparent substrates 1a and 1b opposed to each other at a predetermined interval. Of these, the light reflecting side 1a may not be transparent. . On the surface of the transparent substrate 1a facing the transparent substrate 1b, a reflection layer having a flat reflection surface and capable of storing polarized light is provided.
A mirror reflector 2, which is also a display electrode, is provided, on which an alignment film 3a for controlling the alignment direction of liquid crystal molecules is formed. A scattering plate (scattering layer) 4 for scattering light is provided on a surface of the transparent substrate 1b facing the transparent substrate 1a, and a transparent electrode 5 and a transparent electrode 5 for controlling the alignment direction of liquid crystal molecules are provided thereon. The alignment films 3b are formed in the same order. A GH liquid crystal layer 6 containing a polychromatic dye and a chiral agent is interposed between the alignment films 3a and 3b.
Is pinched. The GH liquid crystal layer 6 has a spontaneous twist structure due to the absorption of the polychromatic dye and the addition of the chiral agent.

The modulation control means 50 controls the GH liquid crystal cell 6
1, the orientation state of the GH liquid crystal layer 6 is controlled by an electric field which is an external field by a voltage applied between the specular reflector 2 and the transparent electrode 5 and is connected to the specular reflector 2 and the transparent electrode 5; The light intensity of the reflected light is modulated and controlled.

Next, an example of a method of manufacturing the GH liquid crystal cell 61 of the first prerequisite liquid crystal display element having the above configuration will be described.

The transparent substrates 1a and 1b have a thickness of 1.
A 1 mm 7059 glass substrate (trade name, manufactured by Corning Glass Works) is used. Aluminum is formed on a glass substrate serving as the transparent substrate 1a by a sputtering method to form the mirror-surface reflecting plate 2. On a glass substrate to be the other transparent substrate 1b, plastic beads having a diameter of 3 μm are dispersed in a thermosetting resin on the surface, and formed into a uniform film thickness by a spin coating method, and then fired. Then, the scattering plate 4 having a thickness of 8 μm is formed by curing. Then, an ITO film is further formed on the scattering plate 4 by a sputtering method to form the transparent electrode 5.

Next, an SE-150 polyimide (manufactured by Nissan Chemical Industries, Ltd.) film is uniformly formed on the specular reflection plate 2 on the transparent substrate 1a and the transparent electrode 5 on the transparent substrate 1b by spin coating. Rubbing after firing,
The alignment layers 3a and 3b are formed. The rubbing direction is set so as to realize alignment of liquid crystal molecules twisted by 240 degrees between the upper and lower substrates.

Next, a glass fiber spacer (manufactured by Nippon Electric Glass Co., Ltd.) having a diameter of 5 μm (not shown) for keeping the distance between the liquid crystal layers 6 constant is sprayed on both or one of the transparent substrates 1a and 1b. An adhesive sealing material mixed with a glass fiber spacer having a diameter of 5.3 μm as a stop layer is screen-printed. After that, the alignment films of the transparent substrates 1a and 1b are bonded together.

Thereafter, a liquid crystal which becomes the GH liquid crystal layer 6 by vacuum degassing is injected between the transparent substrates 1a and 1b.
The H liquid crystal cell 61 is manufactured.

Here, glass substrates are used as the transparent substrates 1a and 1b, but quartz or plastic substrates can also be used. In addition, the thickness of the scattering plate 4 is set to 8 μm, but the thickness is not limited to this. By performing spin coating a number of times, a thicker film can be produced, and the scattering intensity can be increased. . In addition, the method of manufacturing the scattering plate 4 is not limited to the above method, and for example, a method using a hologram can be used.

The thickness (cell thickness) of the GH liquid crystal layer 6 is 5
Although set to μm, the thickness is not particularly limited to this value, and may be any thickness as long as sufficient visible light absorption can be obtained and a practical response speed to applied voltage can be obtained.
It is preferably about 20 μm.

FIG. 2 shows the refractive index anisotropy (Δn) of the contrast of the GH liquid crystal cell in which the alignment of the liquid crystal molecules is twisted by 240 degrees.
Dependencies are shown. As shown in FIG. 2, the contrast of the GH liquid crystal cell greatly depends on Δn. In particular, when Δn is 0. It can be seen that when the value exceeds 1, the contrast rapidly deteriorates. This is because as the Δn of the liquid crystal increases, the optical rotatory power increases, and as a result, the absorption when no voltage is applied decreases, and a sufficient off-state reflectance cannot be obtained. Therefore, from this figure, Δn is preferably 0.1 or less.

In order to obtain a uniform liquid crystal molecular alignment when no voltage is applied, it is necessary to slightly tilt the liquid crystal molecules from the substrate surface. The angle between the orientation direction of the liquid crystal molecules and the surface of the substrate, that is, the so-called pretilt angle, is preferably about 1 to 20 degrees. However, it was experimentally confirmed that when the pretilt angle was 5 degrees or more, the contrast of the liquid crystal display element was improved. Therefore, the pretilt angle was set to 5 degrees here . The bretilt angle can be controlled by rubbing conditions.

The GH liquid crystal material of the GH liquid crystal layer 6 is prepared as follows. The used liquid crystal is trade name ZLI-
4792 (manufactured by Merck & Co., Ltd.), and the host liquid crystal contains several w
t%. Further, in order to impart a spontaneous twist to the liquid crystal, a few wt% of an optically active substance (trade name: S-81l, manufactured by Merck) is mixed, and the ratio d / d of the cell thickness d to the pitch p is adjusted.
It adjusted so that p might be set to about 0.5.

The value of d / p is not particularly limited to the above value. For example, in the above case, it may be 0.42 or more and 0.91 or less. However, depending on the liquid crystal material used, d / p
Is too large, a striped domain occurs, and good display cannot be realized.
It is necessary to check the margin in advance and adjust the ratio between the cell thickness d and the spontaneous twist pitch p of the liquid crystal.

The effect of the liquid crystal elastic constant on the optical properties was evaluated by calculation based on the extended Jones matrix method. However, since the Jones matrix method can only handle polarization optics, the reflectance of natural light is calculated by dividing it into two eigenmodes, right circularly polarized light and left circularly polarized light, in the twisted liquid crystal. The optical characteristics of the GH liquid crystal of the first premise liquid crystal display element were evaluated by obtaining the average value. As a result, as shown in FIG. 3, when a voltage of the same on-state, the absolute as value is smaller reflectivity spray elastic constant k ₁₁ is high, it was found that bright display can be obtained. Therefore, in order to obtain a brighter display with a constant applied voltage, the value of k _11, the better small. Specifically, the value of k ₁₁ is desirably 10 piconewtons (pN) or less. Further, as shown in FIG. 4, when the same on-state voltage is applied, the smaller the value of the ratio k ₃₃ / k ₁₁ of the elastic constant between the bend and the spray, the higher the reflectivity and the brighter the display. Understand. Therefore, to obtain a brighter display with a constant applied voltage, the smaller the value of k ₃₃ / k ₁₁ , the better. Specifically, the value of the ratio is desirably 1.27 or less.

FIG. 5 shows the same manufacturing procedure as above.
FIG. 7 shows the applied voltage dependency of the reflectance when the twist angles of the liquid crystal molecules are set to 180 degrees and 90 degrees (as shown in FIG. 7, 180 degrees is the twist angle at which the reflectance is high when the voltage is applied. And 90 degrees is a twist angle where the reflectivity at the time of applying a voltage is low.) FIG. 5 shows that the first premise liquid crystal display element manufactured here has a high reflectance when a voltage is applied and can realize an extremely bright display.

FIG. 7 shows that the range of the torsion angle at which the reflectivity is 50% or more is 0 to 50 degrees, and 140 to 140 degrees.
Degrees or more and 250 degrees or less. Therefore, a preferable twist angle in terms of brightness is 0 degree or more and 50 degrees or less, and 14 degrees or less.
0 degrees or more and 250 degrees or less. Further, since the maximum value of the reflectance appears in principle at a period of π radians, a twist angle obtained by adding an integral multiple of π radians to the above-mentioned range of the twist angle is also preferable. It should be noted that a numerical value with a reflectance of 50% is about the same brightness as that of a normal newspaper, and a very easy-to-read display is obtained.

On the other hand, the contrast improves as the twist angle increases. In other words, when no voltage is applied, the absorption of light by the polychromatic dye is more effectively performed as the twist angle increases, the reflected light intensity can be made much smaller than the incident light intensity, and the dark display becomes darker and the contrast becomes darker. Is improved. However, on the other hand, as the torsion angle increases, the margin of d / p described above becomes narrower, and hysteresis occurs.

In view of the above, it can be said that the twist angle suitable for the reflection type liquid crystal display element, which is bright, has high contrast, and is capable of halftone display is preferably in the range of 140 to 250 degrees.

FIG. 6 shows the applied voltage dependence of the reflectance of the first premise liquid crystal display element. From this graph, it can be seen that a steep threshold characteristic can be realized and a bright and high contrast can be realized.

Moreover, in the case of the first premise liquid crystal display element, since the combination of the specular reflection plate 2 and the scattering plate 4 having a substantially flat reflection surface is used, there is no need to form irregularities on the reflection layer.
Therefore, the liquid crystal molecules can be favorably aligned to the set twist angle in a narrow region of d / p margin such as a twist angle of 240 degrees. As a result, good display can be realized without generating a striped domain when a voltage is applied.

Further, the scattering plate 4 eliminates the problem of the reflection of the external world by the specular reflection plate 2 and the problem of narrowing the visual field range, and has a wide visual field range, which is suitable for large-capacity display. The specular reflector 2 also has an excellent feature that it is easy to manufacture.

In the first premise liquid crystal display element, since the GH liquid crystal is twisted 240 degrees, halftone can be displayed without obtaining hysteresis while obtaining sufficient brightness and contrast, but the twist angle is limited to this. Is not
If a halftone is not displayed, a mode using a chiral nematic liquid crystal in which liquid crystal molecules are vertically aligned at both substrate interfaces and a polychromatic dye is added can be used.

Although a liquid crystal material having a positive dielectric anisotropy is used here, the same applies to the case where the liquid crystal material having a negative dielectric anisotropy is used and the liquid crystal material is slightly inclined from vertical. In this case, in the dark display, the darkness is slightly inferior to the above, but in the light display, the liquid crystal molecules near the substrate rise almost vertically, so that light absorption hardly occurs and the display is brighter. The display will be obtained.

Further, as the GH liquid crystal layer 6, a photopolymerizable polymer is added to a GH liquid crystal to which a chiral agent has been added.
A so-called polymer network GH liquid crystal mode in which the polymer is photopolymerized after the liquid crystal is introduced into the cell can also be used. In this case, display with good contrast can be realized by sufficiently absorbing light in dark display.

The same effect as described above can be achieved by using the so-called NCAP method in which the GH liquid crystal to which the chiral agent is added is microencapsulated and dispersed in a resin to form a liquid crystal cell as the GH liquid crystal layer 6. it can.

FIG. 8 shows another reflection type liquid crystal display element (hereinafter referred to as a second type) which is a premise of the reflection type liquid crystal display element of the present embodiment.
(Referred to as a liquid crystal display element) is shown in a sectional view.
For convenience of explanation, the first prerequisite liquid crystal display element described above is used.
Members having the same functions as in the case of
And description thereof is omitted .

As shown in FIG. 8, the second premise liquid crystal display element comprises a GH liquid crystal cell 62 and modulation control means 50 connected to the GH liquid crystal cell 62.

The GH liquid crystal cell 62 has transparent substrates 1a and 1b opposed to each other at a predetermined interval, and a mirror reflector 12 is provided on a surface of the transparent substrate 1a facing the transparent substrate 1b. A quarter-wave plate (hereinafter referred to as a λ / 4 plate) 7 which is a birefringent layer having optical birefringence, a transparent electrode 5a, and an alignment for controlling the alignment direction of liquid crystal molecules are formed thereon. The films 3a are formed in this order. Here , the above λ /
The four plates 7 are set so as to satisfy the λ / 4 condition at a wavelength of 550 nm. On the surface of the transparent substrate 1b facing the transparent substrate 1a, a scattering plate 4, a transparent electrode 5b, and an alignment film 3b for controlling the alignment direction of liquid crystal molecules are provided in this order. The GH liquid crystal layer 6 containing a polychromatic dye and a chiral agent is sandwiched between the alignment films 3a and 3b.

The modulation control means 50 controls the GH liquid crystal cell 6
2, the orientation state of the GH liquid crystal layer 6 is controlled by an electric field which is an external field by a voltage applied between the transparent electrodes 5a and 5b, and the light intensity of the reflected light is reduced. The modulation is controlled.

An example of a method for manufacturing the GH liquid crystal cell 62 of the second premise liquid crystal display device having the above configuration will be described.

The transparent substrates 1a and 1b have been described earlier.
The first can be used as assumptions liquid crystal display device similar to the, on a glass substrate serving as a transparent substrate 1a, a first assumption crystal was
The specular reflector 12 is formed in the same manner as in the case of the specular reflector 2 of the display element . Next, an alignment film (not shown) is uniformly formed on the specular reflection plate 12 by spin coating, baked, rubbed, and further coated with an acrylic liquid crystalline polymer solution. Then, the λ / 4 plate 7 is formed by heating the glass transition temperature or higher and then gradually cooling it.
The method of forming the λ / 4 plate 7 is not limited to the above-described method. For example, as disclosed in JP-A-7-72331, polycarbonate or polyvinyl having a λ / 4 retardation is used. It can also be obtained by attaching a polymer film made of an alcohol resin with a transparent adhesive. The λ / 4 plate 7 is designed to satisfy the 波長 wavelength condition at a wavelength of 550 nm, and specifically, adjusts the film thickness so that the optical retardation becomes approximately 140 nm.

On the other hand, the scattering plate 4 is placed on the transparent substrate 1b .
(1) The transparent electrode 5b is formed by a method similar to that of the liquid crystal display element, and further, an ITO film is formed by a sputtering method. The alignment films 3a and 3b are also made of the first prerequisite liquid crystal.
It is formed by the same method as the display element . However, the rubbing directions of the transparent substrate 1a and the transparent substrate 1b are parallel to each other so that the liquid crystal molecules are oriented at a twist angle of 180 degrees.

Thereafter, the transparent substrates 1a and 1b are bonded together in the same manner as the first premise liquid crystal display element, and the substrates 1a and 1b are bonded together.
Between 1b, a liquid crystal which becomes the GH liquid crystal layer 6 by vacuum degassing is injected, and thereby a GH liquid crystal cell 62 is manufactured.

The distance between the GH liquid crystal layers 6 is set to 5 μm in this case, but is not particularly limited and may be any thickness as long as sufficient absorption can be obtained and a practical response speed can be obtained. About 1 to 20 μm is good.

Here, the λ / 4 plate 7 is formed so as to satisfy the 波長 wavelength condition at a wavelength of 550 nm. this is,
This is because the luminosity contrast is improved by optimizing at the wavelength having the highest luminosity. The uniform retardation has the advantage that the manufacturing process is simple and the mass productivity is excellent.

Since the liquid crystal display element having the above-described configuration uses a liquid crystal material having a positive dielectric anisotropy, the light incident on the GH liquid crystal layer 6 from the transparent substrate 1b side when no voltage is applied. Components parallel to the dye molecule are absorbed, and components perpendicular to the dye molecule are transmitted without being absorbed. Therefore, the transmitted light is strongly polarized and enters the λ / 4 plate 7.
The light that has not been absorbed enters the optical axis of the λ / 4 plate 7 at an angle of 45 degrees and is converted into circularly polarized light by the optical phase difference of the λ / 4 plate 7. Further, the circularly polarized light reflected by the specular reflector 12 is converted into linearly polarized light by passing through the λ / 4 plate 7 once again. At this time, the polarization direction is rotated by 90 degrees and converted to a direction parallel to the dye molecules. Therefore, it is strongly absorbed when passing through the GH liquid crystal layer 6 again, and the intensity of the reflected light is much smaller than the intensity of the incident light, and a dark display is obtained.

On the other hand, when a voltage is applied, the dye molecules rise together with the liquid crystal molecules, and the light incident on the GH liquid crystal layer 6 is transmitted without being absorbed, and is incident on the λ / 4 plate 7 with almost no polarization. The light that has not been absorbed is not polarized by the λ / 4 plate 7 but is reflected by the specular reflection plate 12 and again
After passing through the four plates 7, it enters the GH liquid crystal layer 6. At this time, the light is not absorbed by the dye molecules, and the incident light is emitted as it is. That is, in this case, the λ / 4 plate 7 loses its effect and hardly contributes to increasing the absorption. Therefore, the display is bright.

When a display is performed in this manner, the conventional reflector having unevenness does not preserve the polarized light due to the depolarizing effect at the time of reflection, so that an ideal operation cannot be obtained.
There was a problem that the contrast deteriorated. However, in the above-described second premise liquid crystal display element , since the mirror reflection plate 12 is used, the light circularly polarized by the λ / 4 plate 7 is reflected as circularly polarized light, and when the light passes through the λ / 4 plate 7 again. , Resulting in linearly polarized light that is rotated exactly 90 degrees. Therefore, since the depolarization effect due to reflection hardly occurs, an ideal operation can be realized, and a reflection type liquid crystal display device with low power consumption and high contrast can be realized.

FIG. 9 shows the applied voltage dependence of the reflectance of the second prerequisite liquid crystal display element produced as described above. From this graph, it can be seen that a steep threshold characteristic can be realized and a bright and high contrast can be realized.

FIG. 10 shows a combination of a GH liquid crystal layer twisted 240 degrees with a λ / 4 plate and a G liquid crystal layer having a parallel orientation.
400n with the combination of H liquid crystal layer and λ / 4 plate
The reflectance in a wavelength range of m to 700 nm is shown. In the parallel orientation and the twist orientation, the reflectance of a bright display when a voltage is applied does not change much. However, the reflectance of dark display when no voltage is applied is greatly different between the two. In the case of the conventional parallel alignment, the absorption at wavelengths of 400 nm to 500 nm and 600 to 700 nm is poor, and the dark display becomes purple instead of black. For this reason, the dark display cannot be said to be good, and the contrast becomes poor. FIG.
5 shows a contrast in a wavelength region of nm to 700 nm.

From the above results, even in the device configuration in which the GH liquid crystal layer is provided with a λ / 4 plate, the twist angle is 140 ° or more and 2 ° or more.
It can be seen that by setting the angle to 50 degrees or less, dark (black) display without coloring is realized, and the contrast is greatly improved.

FIG. 12 shows that the torsion angle of the GH liquid crystal is constant, and that the reflectance of the liquid crystal display element having a λ / 4 plate and the liquid crystal display element having no λ / 4 plate are applied voltage dependency. The result of having investigated is shown. From this figure, it can be seen that by providing a λ / 4 plate in addition to twisting the GH liquid crystal, the threshold characteristics become steeper, and a better contrast can be realized with the same applied voltage.

Here, the twist angle is set to 180 degrees in order to give priority to brightness and increase contrast, but as shown in FIG. 10 and FIG.
An even higher contrast display can be realized by increasing the twist angle.

FIG. 13 is a sectional view showing the structure of the reflection type liquid crystal display device of the present embodiment. For convenience of explanation, first
The first and second liquid crystal display elements described above
Members having the same functions as in the case of
And description thereof is omitted .

As shown in FIG. 13, the present liquid crystal display element
It comprises a GH liquid crystal cell 63 and modulation control means 50 connected to the GH liquid crystal cell 63.

The GH liquid crystal cell 63 is provided with the aforementioned second prerequisite liquid crystal.
It has the same configuration as the GH liquid crystal cell 62 as a display element except for the following two points. That is, one is the scattering plate 4 and the transparent electrode 5 provided on the transparent substrate 1b.
b, a color filter 15 (15a, 15b, 15c) corresponding to each color of red (R), green (G), and blue (B)
Is interposed. The other is a λ / 4 plate 7 '
The point is that the optical retardation giving the quarter wavelength condition of (7a ', 7b', 7c ') is changed for each of the red, green, and blue pixels. 1 for each wavelength of red, green and blue
Since the retardation that gives the 波長 wavelength condition is different, by setting the retardation that gives the と す る wavelength condition according to the wavelength of each color, better display can be realized in color display.

The GH liquid crystal cell 63 is manufactured in substantially the same manner as the GH liquid crystal cell 62 of the second premise liquid crystal display element , except for the λ / 4 plate 7 ′. Therefore, here, the method of manufacturing the λ / 4 plate 7 ′ will be described with reference to FIGS.
This will be described with reference to (i). It should be noted that the specular reflector 12 is omitted in the figure.

After a specular reflector is formed on the transparent substrate 1a, as shown in FIG. 7A, a retardation is applied to the specular reflector so that the wavelength becomes 1/4 wavelength with respect to the red wavelength. An acrylic high polymer liquid crystal solution to be a λ / 4 plate 7 ′ is formed by adjusting the film thickness so as to form a film. Here, the thickness is about 2 μm. A photoresist 3 having high oxygen plasma resistance is formed on the polymer liquid crystal layer 32 thus manufactured.
0 is applied to the entire surface, and the red and green pixel portions are
Exposure is performed by masking with 1.

Next, only the photoresist 30 in the blue pixel portion is removed by development as shown in FIG. Thereafter, as shown in FIG. 3 (c), by dry etching using oxygen plasma, the polymer liquid crystal layer 32 in the blue pixel portion is reduced by only about 25 nm in retardation of the polymer liquid crystal layer 32 in the red pixel portion (green). (A difference between a film thickness having a retardation corresponding to the wavelength of the blue light and a film thickness having a retardation corresponding to the wavelength of the blue light). Here, etching of 0.31 μm is performed, and then the remaining photoresist 30 is removed as shown in FIG.

Next, as shown in FIG. 9E, a photoresist 30 is applied again on the entire surface, and only the red pixel portion is masked with a photomask 31 and exposed. Then, the photoresist 30 in the blue and green pixel portions is removed by development as shown in FIG. Thereafter, as shown in FIG. 3G, the retardation of the polymer liquid crystal layer 32 in the blue and green pixel portions is further reduced by about 25 nm by dry etching using oxygen plasma (a film having a retardation corresponding to the red wavelength). (Difference between thickness and thickness having retardation according to green wavelength) etching is performed.

As a result, a λ / 4 plate 7 ′ having a different retardation for each pixel is formed. Then, as shown in FIG. 3H, after removing the remaining photoresist 30, a thermosetting resin 33 having no optical anisotropy is applied by about 3 μm as shown in FIG. And flatten the surface.

The thus manufactured λ / 4 plate 7 ′
The retardation of the layer 7c 'corresponding to blue is about 113n.
m, the layer 7b 'corresponding to green has a thickness of 138 nm, and the layer 7a' corresponding to red has a thickness of 163 nm.
nm, 552 nm and 652 nm.
This satisfies the four wavelength conditions.

Thereafter, the blue, green and red color filters 15c, 15b and 15a are made to correspond to the blue, green and red layers 7c ', 7b' and 7a 'of the λ / 4 plate 7', respectively. After the alignment, a GH liquid crystal cell is formed by the same method as the above-described second premise liquid crystal display element to manufacture a liquid crystal display element capable of color display.

According to this, it is possible to realize a reflective liquid crystal display device which is bright and has good contrast and color display with good color reproducibility.

[0086] For another embodiment of the [Embodiment 2] The present invention, FIG. 15, it will be described with reference to FIG. 16, as follows. For the sake of convenience, members having the same functions as those described in the above embodiment will be denoted by the same reference numerals, and description thereof will be omitted.

FIG. 15 shows a reflection type liquid crystal display element (hereinafter referred to as a third assumption) which is a premise of the reflection type liquid crystal display element of the present embodiment.
(Referred to as a liquid crystal display element) is shown in a sectional view.

As shown in FIG. 15, the third premise liquid crystal display element comprises a liquid crystal cell 64 and modulation control means 50 connected to the liquid crystal cell 64.

The liquid crystal cell 64 has a pair of transparent substrates 1a and 1b opposed to each other at a predetermined interval. A flat reflecting surface is provided on the transparent substrate 1a facing the transparent substrate 1b. And a specular reflection plate 12 capable of preserving polarized light, on which a retardation plate (retardation layer) 16, which is a birefringent layer having optically birefringence, a transparent electrode 5a, alignment of liquid crystal molecules is provided. An alignment film 3a for controlling the direction is formed. A scattering plate 4 which is a scattering layer for scattering light is provided on a surface of the transparent substrate 1b facing the transparent substrate 1a, and a polarizer 17, a transparent electrode 5b,
Alignment films 3b for controlling the alignment direction of liquid crystal molecules are formed in the same order. A liquid crystal layer 18 that exhibits optical birefringence is sandwiched between the alignment films 3a and 3b.

By providing such a scattering plate 4 and a polarizer 17 in a cell, parallax due to the thickness of the transparent substrate 1b is eliminated. The position of the retardation plate 16 may be between the specular reflection plate 12 and the liquid crystal layer 18 as described above, or the liquid crystal layer 1.
8 and the polarizer 17.

In forming the phase difference plate 16 , the wavelength is set to 550 nm here . This is because the luminosity contrast is improved by optimizing at the wavelength having the highest luminosity. Such uniform retardation has an advantage that the manufacturing process is simple and excellent in mass productivity.

The modulation control means 50 is connected to the transparent electrodes 5a and 5b in the liquid crystal cell 64, and changes the alignment state of the liquid crystal layer 18 by an electric field which is an external field by a voltage applied between the transparent electrodes 5a and 5b. Control and modulation control of the light intensity of the reflected light.

Third Assumption The method of manufacturing the liquid crystal cell 64 of the liquid crystal display element is that the liquid crystal layer 18 does not contain a dye exhibiting polychromaticity and a chiral agent, uses the polarizer 17, and has a birefringence. The liquid crystal display according to the first embodiment except that a retardation plate 16 is provided instead of the λ / 4 plate 7 ′ as a layer.
Since it is the same as the illustrated element , a method for manufacturing the polarizer 17 will be described here.

The polarizer 17 forms a polarizing film by dispersing a polychromatic dye, for example, iodine or the like, in PVA (polyvinyl alcohol), processing this into a sheet, and uniaxially stretching it. By using an ultraviolet-curable resin on the transparent substrate 1b on which the scattering plate 4 is formed. The method for producing the polarizer is not limited to the above-described method.
The technique disclosed in Japanese Patent Publication No. 5 (1993), that is, P
A polymer film of VA, polyamideimide, polyvinyl chloride, or the like is applied, and a rubbing treatment is performed so as to have a predetermined angle with the orientation direction of the liquid crystal. Then, the rubbed polymer film is treated with potassium iodide. Alternatively, it can be prepared by applying or dipping a solution in which iodine is mixed with potassium, or an aqueous solution in which a dichroic dye such as disazo, trisazo, or dianisidine is dispersed.

The operating principle of the third premise liquid crystal display element is as follows.
The display is performed by compensating the optical retardation of the liquid crystal layer 18 and the optical retardation of the retardation plate 16. For example, a dark display can be realized by adjusting the retardation of both to １ ／ wavelength without applying a voltage to the liquid crystal layer 18, and a bright display by adjusting the retardation of both to 0 or １ ／ wavelength. realizable. When a voltage is applied to the liquid crystal layer 18 in this state, the total retardation of the two changes, and the reflectance changes. That is, as described above, by changing the retardation of the liquid crystal layer 18, the intensity of the reflected light is modulated to perform display.

As for the detailed operation, see, for example, JP-A-6-11711 and Jpn. J. Appl. Ph
ys. 34, page L177. When the liquid crystal molecules have a twisted orientation, the operation becomes more complicated because the optical rotation is added to the birefringence (for details, for example, Prc. Of Japan Disp.
layer'89 Digest ofTec. Peper
See page 192).

According to the above third liquid crystal display element, since the polarizer 17 is used, the first liquid crystal display element and the second liquid crystal display element are used .
Although the display is slightly darker than the liquid crystal display element and the liquid crystal display element of Embodiment 1 , the contrast and color reproducibility are good because the ECB mode, which is superior in contrast to the GH method, is used. Since the plate 4 is provided in the liquid crystal cell, a high-definition and high-quality reflective liquid crystal display element having no parallax can be realized.

FIG. 16 is a sectional view showing the structure of the reflection type liquid crystal display device of the present embodiment. For convenience of explanation, first
It has the same functions as those of the third premise liquid crystal display element described.
The same reference numerals are given to the members to be described, and the description thereof will be omitted.
You .

As shown in FIG. 16, the liquid crystal display device of this embodiment comprises a liquid crystal cell 65 and modulation control means 50 connected to the liquid crystal cell 65.

The liquid crystal cell 65 has the same configuration as the liquid crystal cell 64 of the third premise liquid crystal display element except for the following two points. That is, one is that between the polarizer 17 provided on the transparent substrate 1b and the transparent electrode 5b, the color filters 15 (15a, 15a, 15b, 15c). The other is a retardation plate 16 '(16
a ', 16b', 16c ') is that the optical retardation is changed for each of the red, green and blue pixels. Since the optimum retardation differs for each of the red, green, and blue wavelengths, by setting the retardation according to the wavelength of each color, the color display and the color reproducibility become better in color display.

The liquid crystal layer 18 performs display by birefringence.
The operation principle is basically the same as that of the third prerequisite liquid crystal display element, and the description is omitted.

[0102] The liquid crystal cell 65, retardation plate 16 'except for being manufactured in substantially the third assumption same manner as the liquid crystal cell 64 of the liquid crystal display device, a retardation plate 16', the first embodiment λ It can be manufactured in the same manner as the / 4 plate 7 '. However, the optical retardation of the retardation plate 16 ′ needs to be optimized by the retardation of the liquid crystal layer 18.

According to the above-mentioned liquid crystal display device, a high-definition and high-quality reflective liquid crystal display device having better contrast and color reproducibility than the third prerequisite liquid crystal display device can be realized.

The liquid crystal display, which is the prerequisite for each of the above, is described.
Each of the device and the liquid crystal display device of each embodiment has been described by exemplifying the case of a single liquid crystal cell.
T (Thin Film Transistor) and MIM (Metal-Insulate
Obviously, large-capacity display can be performed by combining with an active element such as r-Metal).

[0105]

As described above, the reflection type liquid crystal display device according to the first aspect of the present invention contains at least one of a pair of transparent substrates and a polychromatic dye sandwiched between the pair of substrates.
A liquid crystal layer, an electrode for applying a voltage to the liquid crystal layer, and a liquid crystal layer between the transparent substrate and the liquid crystal layer of the pair of substrates.
And a flat reflective surface disposed between the liquid crystal layer and the substrate, which may not be transparent, of the pair of substrates.
A reflective layer having , and disposed between the reflective layer and the liquid crystal layer.
And a quarter-wave layer, the optical retardation of the 1/4 wavelength layer is changed in accordance with a wavelength having a color corresponding to the pixel for each pixel, and the liquid crystal layer,
A chiral agent is further added so that the liquid crystal molecules
Twisted about a helical axis perpendicular to the surface,
The twist angle of the liquid crystal molecules from one side of the substrate to the other is 14
The configuration is in a range of 0 degree or more and 250 degrees or less .

As a result, a sufficient contrast can be obtained.
Reflective liquid crystal display capable of multicolor display with good color reproduction
There is an effect that the element can be realized.

[0107]

[0108] Thus, in the reflection type liquid crystal display device using a bright GH liquid crystal system, plays an improved effective contrast, bright, and also to effect an excellent reflection-type liquid crystal display device of high contrast can be realized I'll play it.

The reflection type liquid crystal display device according to the second aspect of the present invention comprises a pair of substrates , at least one of which is transparent.
A liquid crystal layer optically birefringent sandwiched between substrates of
An electrode for applying a voltage to the liquid crystal layer, and the pair of substrates
Layer disposed between the transparent substrate and the liquid crystal layer
And a polarizer disposed between the scattering layer and the liquid crystal layer,
A substrate which is not required to be transparent among a pair of substrates and a liquid crystal layer;
A reflective layer having a flat reflective surface disposed between
Between the layer and the liquid crystal layer or between the liquid crystal layer and the polarizer
A retardation layer disposed on the substrate, wherein the optical characteristics of the retardation layer
Pixelated retardation for each pixel
The configuration is changed according to the wavelength of the color .

As a result, a sufficient contrast can be obtained.
Reflective liquid crystal display capable of multicolor display with good color reproduction
There is an effect that the element can be realized. In addition, with this, in the reflective liquid crystal display device of the ECB mode having excellent contrast, the problem of parallax is solved, and in the relationship between the retardation and the reflectance, the bright display / dark display using the maximum value / minimum value is realized. , The brightness and the contrast are further improved, and a bright and high-contrast reflection-type liquid crystal display element can be realized.

According to a third aspect of the present invention, there is provided a method of manufacturing a reflection type liquid crystal display device, wherein at least one of the substrates is a pair of transparent substrates, a liquid crystal layer sandwiched between the pair of substrates, and a voltage is applied to the liquid crystal layer. An electrode for applying a voltage, a reflective layer disposed between the liquid crystal layer and the non-transparent substrate of the pair of substrates, and an optically birefringent such as a quarter-wave layer or a retardation layer. A reflective birefringent layer, wherein the optical retardation of the birefringent layer is changed according to the wavelength of the color for each of red, green and blue pixels. In the production of the birefringent layer, after adjusting the thickness of the material layer to be a birefringent layer so as to have a retardation according to the red wavelength, only the blue pixel portion, the retardation according to the green wavelength With film thickness and retardation according to blue wavelength Then, each pixel portion of green and blue is etched by the difference between the film thickness having retardation according to the red wavelength and the film thickness having retardation according to the green wavelength. is there.

Thus, a birefringent layer that is changed according to the wavelength of the color for each of the red, green, and blue pixels can be manufactured in a smaller number of steps than in the case where the birefringent layers are separately manufactured for each color. Therefore, there is an effect that the manufacturing process of the reflective liquid crystal display element capable of color display according to the first and second aspects can be simplified.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a configuration of a reflection type liquid crystal display element as a premise of the present invention.

FIG. 2 is a graph showing the refractive index anisotropy of contrast in a 240 degree twisted GH type liquid crystal display device.

FIG. 3 is a graph showing the applied voltage dependence of the reflectance when the splay elastic constant k ₁₁ is used as a parameter.

FIG. 4: Ratio of elastic constant between bend and spray k ₃₃ / k ₁₁
6 is a graph showing the dependence of the reflectance on the applied voltage when is a parameter.

FIG. 5 is a graph showing a change in reflectance when a voltage is applied when a twist angle of liquid crystal is changed in a GH type liquid crystal display element.

6 is a graph showing the applied voltage dependence of the reflectance of the reflective liquid crystal display device of FIG. 1 having a twist angle of 240 degrees.

FIG. 7 is a graph showing the dependence of the reflectance on the torsion angle in the reflective liquid crystal display device of FIG . 1 ;

FIG. 8 is a cross-sectional view showing a configuration of another reflection type liquid crystal display element which is a premise of the present invention.

9 is a graph showing the applied voltage dependence of the reflectance in the reflective liquid crystal display device of FIG. 8 having a twist angle of 180 degrees.

10 shows the wavelength dependence of the reflectance of the reflective liquid crystal display device of FIG. 8 having a twist angle of 240 degrees and the reflective liquid crystal display device in which a λ / 4 plate is combined with a parallel-aligned GH liquid crystal layer. It is a graph.

11 is a graph showing the wavelength dependence of the contrast between the reflective liquid crystal display device of FIG. 8 having a twist angle of 240 degrees and the reflective liquid crystal display device in which a λ / 4 plate is combined with a parallel-aligned GH liquid crystal layer. It is.

FIG. 12 shows the application of the reflectance between the reflective liquid crystal display device of FIG . 8 and the reflective liquid crystal display device having the same twist angle as the reflective liquid crystal display device and not combining the GH liquid crystal layer with a λ / 4 plate. 5 is a graph showing voltage dependency.

FIG. 13 is a cross-sectional view illustrating a configuration of a reflective liquid crystal display element according to Embodiment 1 of the present invention.

FIG. 14 is a process sectional view illustrating the method for manufacturing the λ / 4 plate in the first embodiment.

FIG. 15 is a cross-sectional view showing a configuration of still another reflection type liquid crystal display element which is a premise of the present invention.

FIG. 16 is a cross-sectional view illustrating a configuration of a reflective liquid crystal display element according to Embodiment 2 of the present invention.

FIG. 17 is a perspective sectional view of a main part showing a configuration of a conventional reflective liquid crystal display element.

FIG. 18 is a perspective sectional view of a main part showing a configuration of another conventional reflection type liquid crystal display element.

[Explanation of symbols]

1a Transparent substrate (substrate) 1b Transparent substrate (substrate) 2 Specular reflector (reflection layer / electrode) 3a Alignment film 3b Alignment film 4 Scattering plate (scattering layer) 6 Liquid crystal layer 7 λ / 4 plate (1/4 wavelength layer, birefringent layer) 7 'lambda / 4 plate (1/4 wavelength layer, the birefringent layer) 12 specular reflector (reflective layer) 15 color filter 16 a phase difference plate (phase difference layer, the birefringent layer) 16' retarder (Retardation layer, birefringent layer) 17 polarizer 18 liquid crystal layer

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-7-199173 (JP, A) JP-A-9-90431 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02F 1/1335 520 G02F 1/1335 510 G02F 1/133 500 G02F 1/137 500

Claims (3)

(57) [Claims] 1. A pair of substrates, at least one of which is transparent; a liquid crystal layer containing a polychromatic dye sandwiched between the pair of substrates; an electrode for applying a voltage to the liquid crystal layer ; Between the transparent substrate and the liquid crystal layer.
Scattering layer, a reflective layer having a flat reflective surface disposed between the substrate and the liquid crystal layer which may not be transparent among the pair of substrates, and between the reflective layer and the liquid crystal layer. A quarter-wave layer disposed, wherein the optical retardation of the quarter-wave layer is changed for each pixel according to the wavelength of the color corresponding to the pixel, and the liquid crystal layer is The chiral agent is further added to the liquid
Crystal molecules centered on a spiral axis perpendicular to the surface of a pair of substrates
Liquid crystal from one side of the pair of substrates to the other
The torsion angle of the molecule is in the range of 140 degrees or more and 250 degrees or less.
Reflection type liquid crystal display element characterized by that. 2. A pair of substrates, at least one of which is transparent, and an optically birefringent liquid crystal layer sandwiched between the pair of substrates.
An electrode for applying a voltage to the liquid crystal layer ; and an electrode between the transparent substrate and the liquid crystal layer of the pair of substrates.
Scattering layer, a polarizer disposed between the scattering layer and the liquid crystal layer, and a substrate that is not required to be transparent among the pair of substrates and a liquid crystal.
A reflective layer having a flat reflective surface disposed between the reflective layer and the liquid crystal layer, or a liquid crystal layer and the polarizer.
And a retardation layer disposed in any one of the pixels, wherein the optical retardation of the retardation layer is
Changed according to the wavelength of the color corresponding to that pixel
Reflection type liquid crystal display element characterized by there. 3. A pair of substrates, at least one of which is transparent,
A liquid crystal layer sandwiched between a pair of substrates, and a voltage applied to the liquid crystal layer.
And a transparent electrode of the pair of substrates.
A reflective layer disposed between the substrate and the liquid crystal layer;
Birefringence showing optical birefringence such as / 4 wavelength layer and retardation layer
And a layer, the optical retardation of the birefringent layer,
It changes according to the wavelength of the color for each of the red, green and blue pixels.
A method of manufacturing a reflective liquid crystal display device, comprising : forming a birefringent layer by changing a film thickness of a material layer to be a birefringent layer in accordance with a red wavelength in producing the birefringent layer.
After adjusting so that only the blue pixels
With a film thickness having a retardation corresponding to the green wavelength and a blue
Only the difference in film thickness with retardation according to the wavelength of
Etch, then each pixel part of green and blue, red wave
Film thickness with retardation corresponding to length and green wavelength
Etching by the difference in film thickness with the same retardation
A method for manufacturing a reflection type liquid crystal display device.