JP2003161938A - Liquid crystal display element and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display element with a high utilization factor of the light and excellent display characteristics and a method for manufacturing the same. <P>SOLUTION: The liquid crystal display element is provided with a selective reflection layer 4. The selective reflection layer is composed of one out of a cholesteric liquid crystal layer, a chiral liquid crystal layer and a layer obtained by polymerizing each of these layers and besides is provided with a helical molecular arrangement. A drive circuit layer 5 including electrodes and wiring to apply voltage to a driving liquid crystal layer is disposed between the driving liquid crystal layer 6 of which the molecular arrangement is variable with voltage application and the selective reflection layer. A circularly polarizing plate with an optical retardation plate 3 and a polarizing plate 2 is disposed on the side of the selective reflection layer opposite to the drive circuit layer. <P>COPYRIGHT: (C)2003,JPO

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 including a reflective liquid crystal display device and a transflective liquid crystal display device, and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, liquid crystal display devices have been applied to various fields such as notebook personal computers, monitors, car navigations, scientific calculators, and small and medium-sized TVs. Among them, the reflection type liquid crystal display element does not require a backlight, and therefore, application to a display for a mobile device such as a mobile PC is being studied in order to take advantage of low power consumption and thin and lightweight.

However, since the conventional reflection type liquid crystal display element displays by utilizing external light like paper, it cannot be used because the display screen becomes dark if the environment itself used is dark. Especially in the dark, it cannot be used at all.

For the above reasons, it is desired to develop a reflection type liquid crystal display device in which the utilization efficiency of light is as high as possible. In order to improve the light utilization efficiency, optimization of polarizing plates, retardation plates, color filters, etc., adoption of guest-host mode without using polarizing plates or color filters, or development of a reflective layer with high reflection efficiency, etc. It is valid.

Among them, as a reflection layer having high reflection efficiency,
A method using a cholesteric liquid crystal has been proposed. The cholesteric reflection layer reflects the circularly polarized light in a specific direction of the light incident on the reflection layer. Since the wavelength range of the reflected light varies depending on the spiral pitch of the cholesteric liquid crystal, by stacking a plurality of cholesteric liquid crystal layers having different pitches, it is possible to reflect only the light in the wavelength range to be reflected. For example, by stacking six or more cholesteric liquid crystal layers, most of the visible light region can be reflected. Such a cholesteric reflective layer absorbs less light than a commonly used metal reflective layer such as Al and therefore has high light utilization efficiency.

Further, in contrast to the problem that the reflective liquid crystal display element described above cannot be used at all in the dark, the reflective layer is a semi-transmissive reflective layer, that is, a transflective layer so that it can be used as a transmissive liquid crystal display element in a dark environment. As a half mirror, a transflective liquid crystal display device equipped with a backlight has also been developed. Furthermore, a semi-transmissive liquid crystal display device using a microlens provided in each pixel by providing a pinhole in the reflective layer has been studied. When this liquid crystal display element is used as a reflection type, the brightness of the display screen is reduced by a pinhole as compared with the reflection type liquid crystal display element. When the liquid crystal display element is used as a transmissive type,
When the light emitted from the backlight is collected by the microlens and passed through the pinhole, the brightness of the display screen similar to that of the transmissive liquid crystal display element can be obtained. Thereby, the brightness of the above-mentioned transflective liquid crystal display device is improved.

Further, by adopting the above-mentioned cholesteric reflective layer as the reflective layer of the semi-transmissive liquid crystal display element, a liquid crystal display element having high light utilization efficiency and high visibility in bright or dark environments is realized. it can. A semi-transmissive liquid crystal display device employing such a cholesteric reflection layer is disclosed in JP-A-2000-171789.

In the semi-transmissive liquid crystal display device using the cholesteric reflection layer, the cholesteric reflection layer and the driving liquid crystal layer for switching the polarization state of light are sandwiched by a pair of circularly polarizing plates including a polarizing plate and a retardation plate. It has been configured. As a result, the light emitted from the backlight is
The circularly polarizing plate turns into a circularly polarized state and enters the cholesteric reflection layer, a part of which is reflected back to the backlight and reflected again by the backlight. Therefore, the light can be recycled, and the light from the backlight can be efficiently used.

[0009]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the liquid crystal display element disclosed in No. 789, a drive circuit for driving the liquid crystal layer is formed on a substrate such as glass. In this case, the cholesteric reflection layer is arranged on 1) the driving circuit, 2) the substrate facing the driving circuit board, or 3) the surface of the driving circuit board opposite to the surface on which the driving circuit is formed. To be done.

However, in the case of 1), a cholesteric reflection layer having a thickness of several μm to several tens of μm is patterned to form through holes, and a liquid crystal driving device arranged on the opposite side with the driving circuit and the cholesteric layer interposed therebetween. It is necessary to electrically connect with the electrodes. It is difficult to process the cholesteric reflective layer with high precision, and the yield is reduced. Also,
Since the cholesteric reflection layer has a large film thickness, it is necessary to form a large area through hole, and there is a problem that the aperture ratio of the liquid crystal display element is reduced.

Further, between the polarizing plate on the backlight side and the cholesteric reflection layer, there are various layers such as a glass substrate, a driving circuit and an alignment film for orienting the cholesteric. Although interface reflection of light occurs between these layers, the light reflected at the interface cannot contribute to display, resulting in light loss. Further, if there is a switching element such as a TFT (thin film transistor) or a metal wiring, the light incident from the backlight side is metallically reflected, and this also becomes a loss that does not contribute to display. In a semi-transmissive liquid crystal display element using a cholesteric reflection layer, it is the principle of improving the light utilization efficiency while performing multiple reflections between the cholesteric reflection layer and the backlight, and thus there is such a loss. The loss due to multiple reflection also increases and the overall light utilization efficiency decreases.

In the case of the above 2), since the drive circuit board is located on the observation side of the liquid crystal display element, the incident light is reflected mainly by the metal portion of the drive circuit. Therefore, it is necessary to take measures to block the reflected light that does not contribute to this display. The countermeasure can be simply taken by combining the polarizing plate on the observing side with a quarter-wave plate, but this limits the film structure on the observing side of the liquid crystal display element, so that the display mode of the liquid crystal is limited. Will end up.

In the case of the above 3), since the cholesteric reflection layer is arranged outside the liquid crystal cell, parallax is caused by the thickness of the glass substrate when the reflective display is performed, and not only the brightness is lowered but also the brightness is lowered. The double image is difficult to see.

The present invention has been made in view of the above points, and an object thereof is to provide a liquid crystal display element which has high light utilization efficiency and good display characteristics and which can be applied to various uses, and a manufacturing method thereof. To do.

[0015]

In order to solve the above problems, a liquid crystal display element according to one embodiment of the present invention is formed by either a cholesteric liquid crystal layer, a chiral liquid crystal layer, or a layer obtained by polymerizing each of the above layers. In addition, the selective reflection layer having a spiral molecular arrangement, the driving liquid crystal layer whose molecular arrangement can be changed by applying a voltage, and the electrode and wiring for applying a voltage to the driving liquid crystal layer are included. A drive circuit layer disposed between the layer and the drive liquid crystal layer, a phase difference plate and a polarizing plate, and a circularly polarizing plate disposed on the side opposite to the drive circuit layer with respect to the selective reflection layer. ,
It is characterized by having.

The method of manufacturing a liquid crystal display element according to one aspect of the present invention includes a step of forming a drive circuit layer including electrodes and wirings for applying a voltage on a substrate, a cholesteric liquid crystal layer and a chiral liquid crystal layer. Or a step of forming a selective reflection layer having a helical molecular arrangement on the drive circuit layer by any of the layers obtained by polymerizing each of the above layers,
A driving liquid crystal layer, which has a driving liquid crystal layer whose molecular alignment can be changed by applying a voltage, a retardation plate and a polarizing plate, and which is disposed on the opposite side of the selective reflection layer from the driving circuit layer, and the driving circuit. Characterized by comprising a step of attaching a retardation plate and a polarizing plate on the selective reflection layer on the side opposite to the layer, and a step of removing the substrate from the drive circuit layer on which the selective reflection layer is formed. There is.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, liquid crystal display elements according to embodiments of the present invention will be described in detail with reference to the drawings.

First, the overall structure of the liquid crystal display element will be briefly described. As shown in FIG. 1, the liquid crystal display element is provided with a cholesteric selective reflection layer 4, and a TFT 10 is provided on the observation side of the cholesteric selective reflection layer. The drive circuit layer 5 including the pixel electrode 12 and a large number of wirings (not shown) is provided. A counter substrate 7 is arranged to face the drive circuit layer 5 with a predetermined gap therebetween, and a drive liquid crystal layer 6 is sealed between the drive circuit layer and the counter substrate. A color filter 14 and a transparent counter electrode 16 are formed on the inner surface of the counter substrate 7.

On the back surface of the cholesteric selective reflection layer 4, a retardation plate 3 and a polarizing plate 2 are sequentially laminated.
Similarly, a retardation plate 8 and a polarizing plate 9 are sequentially stacked on the upper surface of the counter substrate 7. The backlight 1 is provided so as to face the polarizing plate 2.

Next, a more detailed structure of the liquid crystal display device will be described together with its manufacturing method. First, the drive circuit layer 5 for driving the liquid crystal is formed on a substrate (not shown). The drive circuit layer 5 includes a pixel electrode 12 made of a transparent conductor such as ITO and a TFT 1 as a switching element.
0, a signal line wiring for supplying an electric signal, a scanning line for operating a switching element, etc., and is formed by a normal array process. At this time, a substrate having heat resistance, chemical resistance, and light resistance that can withstand the array process is desirable, and glass, quartz, a Si substrate, or the like can be used. Further, a substrate such as a plastic film may be used and the drive circuit may be formed by a process applicable to the substrate.

Further, a color filter can be included in the drive circuit layer 5, and in this case, the alignment with the counter substrate in the subsequent step can be facilitated, and the effect of improving the yield and reducing the cost can be obtained. The color filter is
It may be arranged either on the substrate side of the drive circuit layer 5 or on the cholesteric selective reflection layer 4 side.

The switching element of the drive circuit layer 5 is TF.
Not only T but TFD (thin film diode) may be used,
Alternatively, a simple matrix system may be adopted to form a drive circuit layer having no switching element. When the simple matrix method is adopted, the circuit configuration becomes simple, which is advantageous in terms of yield and cost.

Further, when the light enters the channel portion of the TFT, the switching function may be deteriorated. In this case, it is desirable to form a light shielding pattern at a necessary portion.

Subsequently, the cholesteric selective reflection layer 4 in which cholesteric liquid crystal is polymerized is formed on the drive circuit layer 5. At this time, in order to secure the operational reliability of the TFT, a passivation layer made of an inorganic material such as SiN or an overcoat layer made of a transparent organic material is formed between the drive circuit layer 5 and the cholesteric selective reflection layer 4. You may. Further, the overcoat layer may have a light diffusion function by mixing fine particles such as titanium oxide.

The cholesteric selective reflection layer 4 has a helical molecular arrangement and reflects a part of the circularly polarized light (here, right circularly polarized light) component of a specific direction of the incident light (70% here). It has a function of transmitting the rest (here, 30%). The material of the cholesteric selective reflection layer 4 is not limited as long as it has the above-mentioned function, but here, a cholesteric liquid crystal polymer layer having a spiral pitch that selectively reflects light in the ultraviolet range and a light having a wavelength of 700 nm are selectively reflected. A spiral cholesteric liquid crystal polymer layer was continuously formed and used. According to this configuration,
Due to the interaction effect of the interface, the spiral pitch continuously changes within the layer, and a reflective layer that can be used for displaying light in a wide range from the ultraviolet region to the wavelength of 700 nm is obtained. The cholesteric liquid crystal polymer layer was formed by spin-coating a cholesteric liquid crystal and then performing UV crosslinking and thermal polymerization one or more times.

As the selective reflection layer 4, a cholesteric liquid crystal layer, a chiral liquid crystal layer, or a selective reflection layer obtained by polymerizing each of the above layers can be used.

When forming the cholesteric selective reflection layer 4, an alignment layer made of polyimide or the like can be provided between the drive circuit layer 5 and the cholesteric selective reflection layer 4.
By providing the alignment layer, the cholesteric liquid crystal polymer layer can have a stable alignment, and the selective reflection function can be exhibited without loss.

Further, the reflectance, transmittance, and reflection wavelength regions of the cholesteric selective reflection layer 4 are not limited to the above-mentioned values, and various selections are possible, and a plurality of cholesteric liquid crystal layers selectively reflecting a specific wavelength region are provided. The layers may be laminated to form the cholesteric selective reflection layer 4.

Next, the retardation film 3 is attached onto the cholesteric selective reflection layer 4. The retardation plate 3 has a function as a quarter-wave plate. It is desirable that the retardation plate 3 has a wide band that acts as a quarter-wave plate over a wide range of visible light. For that purpose, the phase difference plate 3 is
A two-wave plate and a quarter-wave plate may be laminated, or a material whose refractive index anisotropy increases with wavelength can be used. By using such a retardation plate, the contrast of the liquid crystal display element is increased and the display quality is improved.

Subsequently, the linear polarizing plate 2 is attached onto the retardation plate 3. At this time, each optical axis is set so that the polarizing plate 2 and the retardation plate 3 are combined to form a circularly polarizing plate. In the present embodiment, the angle between the absorption axis of the polarizing plate 2 and the slow axis of the retardation plate 3 is set to 45 °, and the light incident from the polarizing plate 2 side is set to be substantially right circularly polarized light.

When the retardation plate 3 and the polarizing plate 2 are attached to the cholesteric selective reflection layer 4, it is common to provide an adhesive layer at each interface, but for the purpose of suppressing interface reflection of incident light at each interface. It is desirable that the refractive index of the adhesive layer be substantially the same as that of the adjacent selective reflection layer 4, retardation plate 3 and polarizing plate 2. Alternatively, the same effect can be obtained by omitting the adhesive layer and strongly bonding the retardation plate 3 and the polarizing plate 2 by press working.

From the drive circuit layer 5 and the cholesteric selective reflection layer 4 formed by the above steps, the above-mentioned substrate used for forming the drive circuit layer 5 is peeled off. As a method for peeling the substrate, a method for peeling the buffer layer provided between the substrate and the drive circuit layer 5 by heat treatment, light irradiation or the like to change the quality, mechanical polishing, sandblasting, chemical etching, etc. And the like can be used.

Next, a PI alignment film (not shown) is applied and baked on the drive circuit layer 5 exposed by peeling the substrate, and then the alignment film is subjected to a rubbing treatment. If necessary, a passivation layer, an overcoat layer, and the above-mentioned overcoat layer having a light diffusion function can be provided on the drive circuit layer 5.

Subsequently, an element including the cholesteric selective reflection layer 4 and the drive circuit layer 5 formed as described above,
The opposing substrate 7 and the counter substrate 7 are attached to each other by using a sealing material to produce a cell. On the counter substrate 7, a color filter 14, a transparent electrode to be the counter electrode 16, and an alignment film (not shown) for aligning liquid crystals are formed. Here, the rubbing direction of the alignment film was determined so as to be antiparallel (same direction but opposite direction) in the cell when the liquid crystal cell was assembled.

Further, the color filter is not always necessary, and particularly when the color filter is included in the driving circuit layer 5 side, the color filter on the counter substrate 7 side can be omitted. Furthermore, to keep the cell gap constant,
Before the cholesteric selective reflection layer 4 and the counter substrate 7 are bonded together, it is preferable to disperse micropearls having a uniform particle size as a spacer or to dispose a spacer processed with a resin. Alternatively, it is also highly effective to mix a gap adjusting microfiber with the sealing material.

After that, a liquid crystal is injected into the cell formed in the above process to form the driving liquid crystal layer 6. In this embodiment mode, a normal p-type liquid crystal is used to manufacture a cell with a cell gap of 3.2 μm. As a result, the drive liquid crystal layer 6 is in a homogeneous arrangement according to the rubbing direction.

Finally, the retardation plate 8 and the polarizing plate 9 are attached to the surface of the counter substrate 7 opposite to the liquid crystal cell, and the polarizing plate 2
The backlight 1 is arranged outside the LCD to complete the liquid crystal display element. The retardation plate 8 preferably changes its phase difference value depending on Δnd of the drive liquid crystal layer 6, and the drive voltage can be adjusted by this phase difference value. In the present embodiment, the retardation value of the retardation plate 8 is 80 nm, and the retardation plate 8 is arranged so that the slow axis is in the same direction as the alignment direction of the drive liquid crystal layer 6. Further, the polarizing plate 9 was set so that the absorption axis was at a position of 45 ° with respect to the slow axis of the retardation plate 8, and the retardation plate 8 and the polarizing plate 9 were combined into a left elliptically polarized light. As a result of these configurations, the driving voltage of the liquid crystal display element was 4V.

In order to further improve the contrast, it is desirable that the retardation plate 8 has a laminated structure. For example, by disposing a 270 nm retardation plate on an 80 nm retardation plate so that the slow axes intersect at 60 °, light leakage in black display is reduced and the contrast is improved.

Although the driving liquid crystal layer 6 employs a homogeneous mode in which liquid crystals are homogeneously arranged, the liquid crystal display mode is not limited to this. Vertical alignment mode in which n-type liquid crystal or p-type liquid crystal is vertically aligned, O
CB (Optical Compensated Bend) mode, HAN (Hybrid Aligned Nematic) mode, or horizontally aligned p-type or n-type liquid crystal rotated and displayed in a horizontal plane IPS (in-plane switching) Modes can also be used. I
When the PS mode is adopted, the retardation plate 8 can be omitted. That is, in the liquid crystal display element according to the present embodiment, various liquid crystal display modes can be applied, and the liquid crystal display element can be freely selected in consideration of optical characteristics and cost according to the application.

Next, the display principle of the liquid crystal display device constructed as described above will be described. First, the display principle when used as a transmissive liquid crystal display element will be described. As shown in FIG. 2, the light emitted from the backlight 1 passes through the polarizing plate 2 and the retardation plate 3. At this time, the absorption axis of the polarizing plate 2 and the slow axis of the retardation plate 3 form an angle of 45 °, and the retardation of the retardation plate is selected to be λ / 4. The light passing through 3 becomes circularly polarized light in a specific direction (here, right circularly polarized light). This right circularly polarized light enters the cholesteric selective reflection layer 4 and
% Is reflected and 30% is transmitted. The polarization states of the reflected and transmitted light remain right circularly polarized.

The reflected light passes through the retardation plate 3 and the polarizing plate 2 in the opposite direction, is reflected by the backlight 1, and enters the liquid crystal element again. Repeat this process,
Finally, about 50% of the light emitted from the backlight 1 passes through the cholesteric selective reflection layer 4.

As shown in FIG. 2A, in the pixel in which the voltage is applied to the driving liquid crystal layer 6, the liquid crystal rises almost vertically to the counter substrate 7. At this time, the retardation of the driving liquid crystal layer 6 changes according to the applied voltage, and the retardation of about 60 nm
At that point, the combined retardation value combined with the retardation plate 8 becomes 140 nm, which is the same function as the quarter-wave plate. Therefore, when combined with the polarizing plate 9, it can be considered as a function of a left circularly polarizing plate after all, and the right circularly polarized light incident from the backlight 1 side is absorbed by the polarizing plate 9 to display black.

Further, as shown in FIG. 2B, when the above-mentioned light enters a pixel to which no voltage is applied to the driving liquid crystal layer 6, the liquid crystal molecules of the driving liquid crystal layer 6 are oriented in the horizontal direction. , And functions as a 3/4 wavelength plate by combining with the phase difference plate 8. In this case, when combined with the polarizing plate 9, it is considered to be a right circularly polarizing plate, so that the right circularly polarized light that has entered from the backlight 1 side passes through the polarizing plate 9 as it is, and becomes a color corresponding to the color filter that has passed. Recognized by the user.

Next, the display principle when functioning as a reflection type liquid crystal display element will be described. As shown in FIG. 3, the light incident from the outside of the liquid crystal element passes through the polarizing plate 9, the retardation plate 8 and the driving liquid crystal layer 6 and then passes through the cholesteric selective reflection layer 4.
Incident on. At this time, as shown in FIG. 3A, the light incident on the pixel to which the voltage is applied to the liquid crystal is combined with the polarizing plate 9, the retardation plate 8 and the drive liquid crystal layer 6 as described above to the left circle. Since it functions as a polarizing plate, left circularly polarized light enters the cholesteric selective reflection layer 4. However, the left-handed circularly polarized light passes through the cholesteric selective reflection layer 4 without being reflected, and is absorbed by the polarizing plate 2 to provide black display.

On the other hand, as shown in FIG. 3B, the light incident on the pixel to which the voltage is not applied to the driving liquid crystal layer 6 is, as described above, the polarizing plate 9, the retardation plate 8 and the driving liquid crystal layer. The light becomes a right-handed circularly polarized light by 6 and enters the cholesteric selective reflection layer 4. Therefore, 70% of the right-handed circularly polarized light is reflected by the cholesteric selective reflection layer 4, and the driving liquid crystal layer 6,
The light passes through the phase difference plate 8 and the polarizing plate 9 and is emitted to the outside of the device to provide a bright display.

According to the liquid crystal display device constructed as described above, a drive circuit, a glass substrate, or an alignment film for aligning the cholesteric selective reflection layer is provided between the cholesteric selective reflection layer 4 and the retardation plate 3. not exist. Also, T
The drive circuit layer 5 such as FT is the cholesteric selective reflection layer 4
Since it is on the side opposite to the backlight 1, the loss due to metal reflection does not increase due to recycling. Therefore, it is possible to obtain a liquid crystal display element having high light utilization efficiency and good display characteristics and a method for manufacturing the same.

Since the drive circuit layer 5 is arranged below the drive liquid crystal layer 6 when viewed from the observation side of the liquid crystal display element,
The influence of wiring reflection on the drive circuit layer is small. Therefore, there is no limitation on the polarizing plate 9 and the retardation plate 8, and various display modes can be selected. Therefore, it is possible to obtain a liquid crystal display element having good display characteristics and usable for various purposes and a method for manufacturing the same.

Next, the liquid crystal display element according to the second embodiment of the present invention will be described in detail. As shown in FIG. 4, the liquid crystal display element according to the present embodiment has the above-mentioned first structure.
In the liquid crystal display element according to the embodiment of the present invention, as the driving liquid crystal layer 6, the layer of the microcapsules 20 containing the guest-host liquid crystal is adopted, and accordingly, the retardation plate 8 and the polarizing plate 9 are removed. The other structure is the same as that of the first embodiment, and the same portions are denoted by the same reference numerals and detailed description thereof will be omitted.

The liquid crystal display element having the above-mentioned structure is the above-mentioned first
In the manufacturing process of the liquid crystal display element according to the embodiment of
After coating the microcapsules 20 containing the guest-host liquid crystal on the drive circuit layer 5, the microcapsules are solidified to form a microcapsule layer. Further, the counter substrate 7 having a transparent electrode such as ITO formed thereon is attached onto the microcapsule layer to manufacture.

In the guest-host liquid crystal, when a p-type liquid crystal and a black dye are used, the liquid crystal molecules and the dye lie in the direction parallel to the counter substrate 7 of the liquid crystal display element when no voltage is applied, and the voltage is applied. As a result, the liquid crystal molecules and the dye stand in the vertical direction. Therefore, when no voltage is applied, the incident light is absorbed by the dye to display black, and when a sufficient voltage is applied, the incident light is transmitted without being absorbed by the dye, resulting in white display.

According to the above construction, it is not necessary to provide a polarizing plate and a retardation plate on the viewer side of the liquid crystal display element, and the number of members can be reduced and the manufacturing cost can be reduced. at the same time,
It is possible to obtain a liquid crystal display device having high light utilization efficiency and improved display quality.

It is also possible to form the counter substrate 11 with a material such as a plastic film, or to omit the counter substrate 11. In this case, a lighter and thinner liquid crystal display element can be obtained. When the counter substrate 11 is omitted, a transparent electrode such as ITO may be directly formed on the microcapsule layer.

Furthermore, according to the liquid crystal display element of the second embodiment, the steps of cell production and liquid crystal injection are not required, and the production can be further simplified, and the yield is improved. Moreover, since the liquid crystal is encapsulated in microcapsules, the reliability of the cell is also improved.

In the second embodiment, a black and white guest liquid crystal display element is used as the guest dye, but a colored liquid crystal display element can be used by using a colored dye. For example, as in the third embodiment shown in FIG. 5, by providing a microcapsule layer in which microcapsules 20a, 20b, 20c containing dyes that display different colors such as red, blue and green are arranged side by side, Full-color display is also possible. Further, in the third embodiment, in order to secure a wide color reproduction range, it is preferable to use the retardation plate 8 and the polarizing plate 9 having the function of the quarter wavelength plate.

Although the dyes for displaying red, blue, and green are used in the present embodiment, dyes for displaying yellow, cyan, and magenta, which are complementary colors to the dyes, may be used, and microcapsules containing the respective dyes. By adopting a method in which three layers are vertically stacked to perform color display by subtractive color mixing, it is possible to obtain a liquid crystal display element having a higher light utilization efficiency and a wider color reproduction range.

Besides, the present invention is not limited to the above-described embodiments, but can be variously modified within the scope of the present invention. For example, in the above-described embodiment, the cholesteric selective reflection layer is formed on the drive circuit layer formed on the substrate, and then the substrate is removed. However, the heat resistance of the cholesteric selective reflection layer is improved and the drive circuit layer is It is also possible to directly form the drive circuit layer on the cholesteric selective reflection layer by achieving a low temperature process.

Further, in the above-described embodiment, in order to avoid reflection of the surrounding scenery and obtain a good contrast, the member on the observation side of the liquid crystal display element may be subjected to antiglare or antireflection surface treatment. When a polarizing plate is used on the observation side, such a treatment can be applied to the surface of the polarizing plate, and when a polarizing plate is not used, the surface of the member closest to the observation side can be treated. You may give surface treatment.

[0058]

As described in detail above, according to the present invention,
It is possible to provide a liquid crystal display element having high light utilization efficiency and good display characteristics and applicable to various uses, and a method for manufacturing the same.

[Brief description of drawings]

FIG. 1 is a sectional view showing a liquid crystal display element according to a first embodiment of the present invention.

FIG. 2 is a sectional view for explaining a display principle when the liquid crystal display element is used as a transmissive display element.

FIG. 3 is a sectional view for explaining a display principle when the liquid crystal display element is used as a reflective display element.

FIG. 4 is a sectional view showing a liquid crystal display element according to a second embodiment of the present invention.

FIG. 5 is a sectional view showing a liquid crystal display element according to a third embodiment of the present invention.

[Explanation of symbols]

1 ... Backlight, 2, 9 ... Polarizer, 3, 8 ... Retardation plate, 4 ... Cholesteric selective reflection layer, 5 ... Drive circuit layer, 6 ... Driving liquid crystal layer, 7 ... Counter substrate, 10 ... TFT 12 ... Pixel electrode 14 ... Color filter 16 ... Counter electrode 20 ... Microcapsules,

Claims (10)

[Claims] 1. A cholesteric liquid crystal layer, a chiral liquid crystal layer,
Alternatively, each of the above layers is formed of a polymerized layer, and a selective reflection layer having a helical molecular arrangement, a driving liquid crystal layer whose molecular arrangement can be changed by applying a voltage, and a voltage applied to the driving liquid crystal. A driving circuit layer including an electrode and a wiring for applying a voltage, which is disposed between the selective reflection layer and the driving liquid crystal layer, a retardation plate and a polarizing plate, and with respect to the selective reflection layer. A liquid crystal display device comprising: a circularly polarizing plate disposed on the side opposite to the drive circuit layer. 2. The selective reflection layer and the drive circuit layer are directly
Alternatively, the liquid crystal display element according to claim 1, wherein the liquid crystal display element is adjacently disposed via any one of an adhesive layer, an organic thin film layer, and an inorganic thin film layer. 3. The circularly polarizing plate and the selective reflection layer are arranged adjacent to each other directly or through any one of an adhesive layer, an organic thin film layer and an inorganic thin film layer. The liquid crystal display device according to item 1. 4. The liquid crystal display device according to claim 1, wherein the driving liquid crystal layer includes a plurality of microcapsules each containing a guest-host liquid crystal. 5. A spiral is formed by a step of forming a drive circuit layer including electrodes and wirings for applying a voltage on a substrate, and a cholesteric liquid crystal layer, a chiral liquid crystal layer, or a layer obtained by polymerizing each of the above layers. Forming a selective reflection layer having a circular molecular arrangement on the drive circuit layer, a drive liquid crystal layer capable of changing the molecular arrangement by applying a voltage, a retardation plate and a polarizing plate, and the selective reflection layer A circularly polarizing plate disposed on the side opposite to the drive circuit layer, a step of attaching a retardation plate and a polarizing plate on the selective reflection layer on the side opposite to the drive circuit layer, and the selective reflection layer is And a step of removing the substrate from the formed drive circuit layer, the manufacturing method of the liquid crystal display element. 6. On the removed drive circuit layer of the substrate,
The liquid crystal display device according to claim 5, further comprising: a step of forming a driving liquid crystal layer composed of microcapsules containing guest-host liquid crystals, and a step of forming a transparent electrode on the driving liquid crystal layer. Manufacturing method. 7. On the removed drive circuit layer of said substrate,
6. The method according to claim 5, further comprising: a step of forming a driving liquid crystal layer composed of microcapsules containing guest-host liquid crystal; and a step of attaching an opposite substrate having a transparent electrode formed thereon to the driving liquid crystal layer. A method for manufacturing a liquid crystal display device according to item 1. 8. A step of disposing a counter substrate having a transparent electrode formed thereon so as to face the drive circuit layer from which the substrate has been removed, and forming a drive liquid crystal layer between the counter substrate and the drive circuit layer.
The method for manufacturing a liquid crystal display element according to claim 5, further comprising: 9. The method for manufacturing a liquid crystal display element according to claim 5, wherein the step of removing the substrate includes a step of peeling the substrate from the drive circuit layer. . 10. The method of manufacturing a liquid crystal display element according to claim 5, wherein the step of removing the substrate includes a step of polishing the substrate.